Problem:
 Score : 400 points    Problem Statement For a positive integer X , let f(X) be the number of positive divisors of X .  Given a positive integer N , find \sum_{K=1}^N K\times f(K) .      Constraints  1 \leq N \leq 10^7         Input Input is given from Standard Input in the following format:  N       Output Print the value \sum_{K=1}^N K\times f(K) .        Sample Input 1 4      Sample Output 1 23  We have f(1)=1 , f(2)=2 , f(3)=2 , and f(4)=3 , so the answer is 1\times 1 + 2\times 2 + 3\times 2 + 4\times 3 =23 .       Sample Input 2 100      Sample Output 2 26879       Sample Input 3 10000000      Sample Output 3 838627288460105  Watch out for overflows.

Solution (Python):
def main(sample_file = ''):

    """ convenient functions
    
    
    
    
    
    """

    """convenient decorator
    
    
        
        
        
        
        
        
        
        
        
        
    """
    
    
    import sys
    sys.setrecursionlimit(10**7)
    from itertools import accumulate, combinations, permutations, product 
    
    from math import factorial, ceil, floor, sqrt
    def factorize(n):
        """return the factors of the Arg and count of each factor
        
        Args:
            n (long): number to be resolved into factors
        
        Returns:
            list of tuples: factorize(220) returns [(2, 2), (5, 1), (11, 1)]
        """
        fct = []  
        b, e = 2, 0  
        while b * b <= n:
            while n % b == 0:
                n = n // b
                e = e + 1
            if e > 0:
                fct.append((b, e))
            b, e = b + 1, 0
        if n > 1:
            fct.append((n, 1))
        return fct
    def combinations_count(n, r):   
        """Return the number of selecting r pieces of items from n kinds of items.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        
        if n < 0 or r < 0:
            raise Exception('combinations_count(n, r) not defined when n or r is negative')
        if n - r < r: r = n - r
        if r < 0: return 0
        if r == 0: return 1
        if r == 1: return n
        numerator = [n - r + k + 1 for k in range(r)]
        denominator = [k + 1 for k in range(r)]
        for p in range(2,r+1):
            pivot = denominator[p - 1]
            if pivot > 1:
                offset = (n - r) % p
                for k in range(p-1,r,p):
                    numerator[k - offset] /= pivot
                    denominator[k] /= pivot
        result = 1
        for k in range(r):
            if numerator[k] > 1:
                result *= int(numerator[k])
        return result
    def combinations_with_replacement_count(n, r):
        """Return the number of selecting r pieces of items from n kinds of items allowing individual elements to be repeated more than once.
        
        Args:
            n (long): number
            r (long): number
        
        Raises:
            Exception: not defined when n or r is negative
        
        Returns:
            long: number
        """
        if n < 0 or r < 0:
            raise Exception('combinations_with_replacement_count(n, r) not defined when n or r is negative')
        elif n == 0:
            return 1
        else:
            return combinations_count(n + r - 1, r)
    from bisect import bisect_left, bisect_right
    from collections import deque, Counter, defaultdict 
    from heapq import heapify, heappop, heappush, heappushpop, heapreplace,nlargest,nsmallest 
    from copy import deepcopy, copy 
    import operator
    from operator import itemgetter 
    
    
    from functools import reduce, lru_cache
    def chmin(x, y):
        """change minimum
        if x > y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current minimum value
            y (long): potential minimum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x > y:
            x = y
            return (x, True)
        else:
            return (x, False)
    def chmax(x, y):
        """change maximum
        if x < y, x = y and return (x, True).
        convenient when solving problems of dp[i]
        
        Args:
            x (long): current maximum value
            y (long): potential maximum value
        
        Returns:
            (x, bool): (x, True) when updated, else (x, False)
        """
        if x < y:
            x = y
            return (x, True)
        else:
            return (x, False)

    from fractions import gcd 
    def gcds(numbers):
        return reduce(gcd, numbers)
    def lcm(x, y):
        return (x * y) // gcd(x, y)
    def lcms(numbers):
        return reduce(lcm, numbers, 1)
    def make_divisors(n, reversed=False):
        """create list of divisors
        
        Args:
            number (int): number from which list of divisors is created
            reversed (bool, optional): ascending order if False. Defaults to False.
        
        Returns:
            list: list of divisors
        """
        divisors = set()
        for i in range(1, int(n**0.5)+1):
            if n % i == 0:
                divisors.add(i)
                divisors.add(n//i)
        return sorted(list(divisors),reverse=reversed)
    
    
    
    INF = 10 ** 18
    MOD = 10 ** 9 + 7
    AtoZ = list('abcdefghijklmnopqrsruvwxyz') 
    modpow = lambda a, n, p = MOD: pow(a, n, p) 
    def modinv(a, p = MOD):
        
        
        return modpow(a, p-2, p)
    def modinv_list(n, p = MOD):
        if n <= 1:
            return [0,1][:n+1]
        else:
            inv_t = [0,1]
            for i in range(2, n+1):
                inv_t += [inv_t[p % i] * (p - int(p / i)) % p]
            return inv_t
    def modfactorial_list(n, p = MOD):
        if n == 0:
            return [1]
        else:
            l = [0] * (n+1)
            tmp = 1
            for i in range(1, n+1):
                tmp = tmp * i % p
                l[i] = tmp
            return l
    def modcomb(n, k, fac_list = [], p = MOD):
        
        
        from math import factorial
        if n < 0 or k < 0 or n < k: return 0
        if n == 0 or k == 0: return 1
        if len(fac_list) <= n:
            a = factorial(n) % p
            b = factorial(k) % p
            c = factorial(n-k) % p
        else:
            a = fac_list[n]
            b = fac_list[k]
            c = fac_list[n-k]
        return (a * modpow(b, p-2, p) * modpow(c, p-2, p)) % p
    def modadd(a, b, p = MOD):
        return (a + b) % MOD
    def modsub(a, b, p = MOD):
        return (a - b) % p
    def modmul(a, b, p = MOD):
        return ((a % p) * (b % p)) % p
    def moddiv(a, b, p = MOD):
        return modmul(a, modpow(b, p-2, p))

    class UnionFindTree:
        """union find tree class
        TODO: fix this description...
        how to use (example):
        >>  uf = UnionFindTree(N) 
        >>  if uf.find_root(a) == uf.find_root(b):
        >>      do something
        >>  else:
        >>      do something
        >>      uf.unite(a, b)
        """
        def __init__(self, N):
            self.root = [-1] * (N+1)
            self.rank   = [0]  * (N+1)
            self.connected_num = [1] * (N+1)
    
        def find_root(self,x):
            root = self.root
            while root[x] != -1:
                x = root[x]
            return x
    
        def unite(self,x,y):
            root = self.root
            rank = self.rank
            connected_num = self.connected_num
            find_root = self.find_root
    
            rx = find_root(x)
            ry = find_root(y)
            if rx != ry:
                if rank[rx] < rank[ry]:
                    root[rx] = ry
                    rx,ry = ry,rx
                else:
                    if rank[rx] == rank[ry]:
                        rank[rx] += 1
                    root[ry] = rx       
                connected_num[rx] += connected_num[ry]

    class SegTree:
        """
        ref: https://qiita.com/takayg1/items/c811bd07c21923d7ec69
        init(init_val, ide_ele): 配列init_valで初期化 O(N)
        update(k, x): k番目の値をxに更新 O(logN)
        query(l, r): 区間[l, r)をsegfuncしたものを返す O(logN)
        """
        def __init__(self, init_val, segfunc, ide_ele):
            """
            init_val: 配列の初期値
            segfunc: 区間にしたい操作
            ide_ele: 単位元
            n: 要素数
            num: n以上の最小の2のべき乗
            tree: セグメント木(1-index)
            """
            n = len(init_val)
            self.segfunc = segfunc
            self.ide_ele = ide_ele
            self.num = 1 << (n - 1).bit_length()
            self.tree = [ide_ele] * 2 * self.num
            
            for i in range(n):
                self.tree[self.num + i] = init_val[i]
            
            for i in range(self.num - 1, 0, -1):
                self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

        def update(self, k, x):
            """
            k番目の値をxに更新
            k: index(0-index)
            x: update value
            """
            k += self.num
            self.tree[k] = x
            while k > 1:
                self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
                k >>= 1

        def query(self, l, r):
            """
            [l, r)のsegfuncしたものを得る
            l: index(0-index)
            r: index(0-index)
            """
            res = self.ide_ele
            l += self.num
            r += self.num
            while l < r:
                if l & 1:
                    res = self.segfunc(res, self.tree[l])
                    l += 1
                if r & 1:
                    res = self.segfunc(res, self.tree[r - 1])
                l >>= 1
                r >>= 1
            return res

    
    
    
    
    
    
    
    

    def BellmanFord(N, M, ABC, vertex_start, vertex_end, value_if_inf = -1, find_shortest = False):
        """to calculate furthest or shortest length between vertex_start and vertex_end using BellmanFord algorithm
        
        Args:
            N (int): number of vertices
            M (int): number of edges
            ABC (list): [(ai, bi, ci) for _ in range(N)] where i-th edge is directed from vertex ai to vertex bi and the length is ci 
            vertex_start (int): start vertex. usually use 0.
            vertex_end (int): end vertex. usually use N-1.
            value_if_inf (int or string as you like, optional): value you want when the furthest (or shortest) distance is infinite (or -infinite). Defaults to -1.
            find_shortest (bool, optional): choose False to find furthest path. Defaults to False.
        
        Returns:
            int or string: normally int (but can be str if you set value_if_inf to str)
            
        Example:
                N, M, P = R()
                ABC = [R() for _ in range(M)]
                ABC = [(a-1, b-1, c-P) for a, b, c in ABC]
                print(BellmanFord(N, M, ABC, 0, N-1, value_if_inf = 'inf'))

        """

        def make_reachable_list(N, M, ABC, vertex_start, vertex_end):
            reachable_to_direct = defaultdict(list)
            reachable_from_direct = defaultdict(list)
            reachable_from_start = [False] * N
            reachable_to_end = [False] * N
            reachable_from_start[vertex_start] = True
            reachable_to_end[vertex_end] = True
            reachable_from_both_sides = [False] * N
            dfs_from_start = []
            dfs_to_end = []
            for a, b, c in ABC:
                reachable_to_direct[a].append(b)
                reachable_from_direct[b].append(a)
                if a == vertex_start:
                    dfs_from_start.append(b)
                    reachable_from_start[b] = True
                if b == vertex_end:
                    dfs_to_end.append(a)
                    reachable_to_end[a] = True
            while dfs_from_start:
                v = dfs_from_start.pop()
                for i in reachable_to_direct[v]:
                    if not reachable_from_start[i]:
                        reachable_from_start[i] = True
                        dfs_from_start.append(i)
            while dfs_to_end:
                v = dfs_to_end.pop()
                for i in reachable_from_direct[v]:
                    if not reachable_to_end[i]:
                        reachable_to_end[i] = True
                        dfs_to_end.append(i)
            for i in range(N):
                reachable_from_both_sides[i] = reachable_from_start[i] and reachable_to_end[i]
            return reachable_from_both_sides
        
        reachable_from_both_sides = make_reachable_list(N, M, ABC, vertex_start, vertex_end)
        
        if find_shortest:
            dist = [INF for i in range(N)]
        else:
            dist = [-INF for i in range(N)]
        
        dist[vertex_start] = 0
        for i in range(N):
            updated = False
            for a, b, c in ABC:
                if not reachable_from_both_sides[a]:
                    continue
                elif find_shortest:
                    update_condition = dist[a] + c < dist[b]
                else:
                    update_condition = dist[a] + c > dist[b]
                if dist[a] != INF and update_condition:
                    dist[b] = dist[a] + c
                    updated = True
                    if i == N-1:
                        return value_if_inf
            if not updated:
                break
        return dist[vertex_end]

    
    def warshall_floyd(number_vertex, XYD, shift_one_for_vertex=False):
        
        
        
        
        
        d = [[float("inf")]*number_vertex for i in range(number_vertex)]
        for x, y, dist in XYD:
            if shift_one_for_vertex:
                x = x - 1
                y = y - 1
            d[x][y] = dist
            d[y][x] = dist
        for i in range(number_vertex):
            d[i][i] = 0 
        for k in range(number_vertex):
            for i in range(number_vertex):
                for j in range(number_vertex):
                    d[i][j] = min(d[i][j],d[i][k] + d[k][j])
        return d


    """ initialize variables and set inputs
    
        
        
            
            
    
        
        
        
        
        
        
        
    
        
        
        
        
    
        
        
    """

    
    r = lambda: sys.stdin.readline().strip()
    r_int = lambda: int(r())
    r_float = lambda: float(r())
    R = lambda: list(map(int, r().split()))
    R_str = lambda: r().split()
    R_map = lambda: map(int, r().split())
    R_float = lambda: list(map(float, r().split()))
    R_tuple = lambda: tuple(map(int, r().split()))

    """ how to treat input
    
    
    
    
    
    
    
    """

    
    if sample_file:
        sys.stdin = open(sample_file)
        
    
    
    

    N = r_int()
    l = [0] * N
    for i in range(1, N+1):
        j = 1
        while i * j <= N:
            l[i*j-1] += 1
            j += 1
    ans = 0
    for i, ll in enumerate(l, 1):
        ans += i * ll
    print(ans)


    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    

    


    
    
    

    """memo: how to use defaultdict of list
    
    Dic = defaultdict(list)
    
    Dic[x].append(y)
    
    for k, v in Dic.items():
    """
    
    """memo: how to solve binary problems
    
    >>> a = 5
    >>> bin_str_a = format(a, '
    >>> print(bin_str_a)
    0b0101 
    """
    
    """memo: how to solve the problem
    creating simple test/answer
    greed
    simple dp
    graph
    """

if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())

ans = 0
for i in range(1, int(n ** 0.5) + 1):
    cnt = ((n // i) * (n // i + 1) // 2) - (i * (i + 1) // 2)
    ans += i * cnt * 2 + i ** 2
print(ans)

Solution (Python):
n = int(input())

ans = 0
for i in range(1,n+1):
    num = n//i
    ans += num*(i+i*num)//2

print(ans)

Solution (Python):
n = int(input())

ans = 0
for i in range(1,n+1):
    num = n//i
    ans += num*(i+i*num)//2

print(ans)

Solution (Python):
import sys
input = sys.stdin.readline

N = int(input())
Answer = 0

for i in range(1,N+1):
    cnt = N // i
    num = cnt * (cnt + 1) >> 1
    num *= i
    Answer += num

print(Answer)

Solution (Python):
N = int(input())
print(sum(i*(N//i)*(N//i + 1) // 2 for i in range(1,N+1) ))

Solution (Python):

N = int(input())

Answer = 0

for i in range(1,N+1):
    num = i*(N//i)*(N//i + 1) // 2
    Answer += num

print(Answer)

Solution (Python):
import sys
input = sys.stdin.readline


N = int(input())

Answer = 0

for i in range(1,N+1):
    num = (N//i)*(N//i + 1) // 2
    num *= i
    Answer += num

print(Answer)

Solution (Python):
from numba import njit
@njit('void(i8)')
def f(N):
  Answer = 0
  for i in range(1,N+1):
    num = (N//i)*(N//i + 1) // 2
    num *= i
    Answer += num
  print(Answer)

f(int(input()))

Solution (Python):
import sys
import math
from collections import deque
input = sys.stdin.readline


N = int(input())

Answer = 0

for i in range(1,N+1):
    num = (N//i)*(N//i + 1) // 2
    num *= i
    Answer += num

print(Answer)

Solution (Python):
N = int(input())

ans = 0
for x in range(1, N + 1):
    n = N // x
    ans += n * (2 * x + (n - 1) * x) // 2

print(ans)

Solution (Python):
N = int(input())
ans = 0
for i in range(1, N+1):
    y = N//i
    ans += i*y*(y+1)//2
print(ans)

Solution (Python):
def main():
    n = int(input())

    sum = 0
    for j in range(n):
        j += 1
        
        
        
        k = n // j
        sum += (k * (1 + k) // 2) * j

    print(sum)


if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())

ans = 0
for i in range(1, n+1):
  y = n//i
  ans += i * y * (y+1) // 2
print(ans)

Solution (Python):
N = int(input())

r = 0
for d in range(1, N+1):
	Y = N//d
	r += d * Y * (Y+1)//2
print(r)

Solution (Python):
n = int(input())
ans = 0
for i in range(1, n+1):
    y = n // i
    ans +=( y * (y+1)* i)//2

print(ans)

Solution (Python):
n = int(input())
ans = 0
for i in range(1, n+1):
    for j in range(i, n+1, i):
        ans += j
    

print(ans)

Solution (Python):
import sys

DEBUG=False
if DEBUG:
    f=open("202006_5th/D_input.txt")
else:
    f=sys.stdin
ans_sum=0
n=int(f.readline().strip())
for _ in range(1,n+1):
    num=n//_
    ans_sum+=_*((num*(num+1))//2)
print(ans_sum)

Solution (Python):
import math
n=int(input())
ans=0
for i in range(1,n+1):
  ans+=(i+(n//i)*i)*(n//i)//2
print(ans)

Solution (Python):
from sys import stdin
input = lambda: stdin.readline().rstrip("\r\n")
from collections import defaultdict as vector, deque as que
read = lambda: list(map(int,input().split()))
from bisect import bisect
from heapq import heappush as hpush,heappop as hpop

n,=read()
ans=0
for i in range(1,n+1):
	c=n//i 
	k=(c*(c+1))//2
	ans+=i*k 
print(ans)

Solution (Python):
N = int(input())

ans = 0
for i in range(1, N+1):
    tmp = i*(N//i)
    ans += (N//i)*(tmp+i)//2
print(ans)

Solution (Python):
N = int(input())

t = 0

for i in range (1,N+1):
  p = N//i
  t += i*p*(1+p)/2
  

print(int(t))

Solution (Python):
n = int(input())
res = 0
for i in range(1,n+1):
	k = n//i
	res += i*(k*(k+1)//2)
print(res)

Solution (Python):
import sys
from io import StringIO
import unittest
import os

sys.setrecursionlimit(999999999)

def get_arithmetic_progression(a, d, n):
    return n * (2 * a + (n - 1) * d) // 2


def resolve(test_def_name=""):
    n = int(input())

    ans = 0
    for i in range(1, n + 1):
        ans += get_arithmetic_progression(i, i, n // i)

    print(ans)



class TestClass(unittest.TestCase):
    def assertIO(self, assert_input, output):
        stdout, sat_in = sys.stdout, sys.stdin
        sys.stdout, sys.stdin = StringIO(), StringIO(assert_input)
        resolve(sys._getframe().f_back.f_code.co_name)
        sys.stdout.seek(0)
        out = sys.stdout.read()[:-1]
        sys.stdout, sys.stdin = stdout, sat_in
        self.assertEqual(out, output)

    def test_input_1(self):
        test_input = """4"""
        output = """23"""
        self.assertIO(test_input, output)

    def test_input_2(self):
        test_input = """100"""
        output = """26879"""
        self.assertIO(test_input, output)

    
    
    
    

    
    def tes_t_1original_1(self):
        test_input = """データ"""
        output = """データ"""
        self.assertIO(test_input, output)



if __name__ == "__main__":
    if os.environ.get("USERNAME") is None:
        
        resolve()

    else:
        
        unittest.main()

Solution (Python):
num = int(input())
val = 0
for i in range(1,num+1):
  k = num//i
  val += i*(k*(k+1))//2
print(val)

Solution (Python):
n = int(input())
ans = 0
for i in range(1, n + 1):
    x, y = i, (n // i) * i
    
    ans += ((n // i) * (x + y) // 2)
print(ans)

Solution (Python):
n = int(input())
ans = 0

for i in range(1, n + 1):
    ans += (i + (n//i)*i)*(n//i)//2

print(ans)

Solution (Python):

import sys
import math
from bisect import bisect_left
from bisect import bisect_right
from collections import defaultdict
from heapq import heappop, heappush
import itertools
import random
from decimal import *

input = sys.stdin.readline

def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))
def inputStr(): return input()[:-1]

inf = float('inf')
mod = 1000000007




def main():
	N = inputInt()

	ans = 0
	total = N * (N+1) // 2
	for i in range(1,N+1):
		tmp = i * ((N//i) * ((N//i)+1) // 2)
		ans += tmp

	print(ans)





if __name__ == "__main__":
	main()

Solution (Python):

import sys
import math
from bisect import bisect_left
from bisect import bisect_right
from collections import defaultdict
from heapq import heappop, heappush
import itertools
import random
from decimal import *

input = sys.stdin.readline

def inputInt(): return int(input())
def inputMap(): return map(int, input().split())
def inputList(): return list(map(int, input().split()))
def inputStr(): return input()[:-1]

inf = float('inf')
mod = 1000000007




def main():
	N = inputInt()
	Nnum = [0 for i in range(N+1)]

	for i in range(1,N+1):
		for j in range(i,N+1,i):
			Nnum[j] += 1

	ans = 0
	for i,val in enumerate(Nnum):
		ans += i * val

	print(ans)





if __name__ == "__main__":
	main()

Solution (Python):
def calc(i):
    cnt = n // i
    return (i + i*cnt) * cnt // 2

n = int(input())

ans = 0
for i in range(1, n+1):
    ans += calc(i)

print(ans)

Solution (Python):
import bisect, collections, copy, heapq, itertools, math, string, sys
input = lambda: sys.stdin.readline().rstrip() 
sys.setrecursionlimit(10**7)
INF = float('inf')
def I(): return int(input())
def F(): return float(input())
def SS(): return input()
def LI(): return [int(x) for x in input().split()]
def LI_(): return [int(x)-1 for x in input().split()]
def LF(): return [float(x) for x in input().split()]
def LSS(): return input().split()

def resolve():
    N = I()

    ans = 0
    for i in range(1, N + 1):
        num = N // i
        e = num * i
        ans += (i + e) * num // 2

    print(ans)

if __name__ == '__main__':
    resolve()

Solution (Python):
n = int(input())

ans = 0
for i in range(1, n + 1):
  A = i
  D = i
  N = n // i
  ans += N * (2 * A + (N - 1) * D) // 2

print(ans)

Solution (Python):
N=int(input())
ans = 0
for i in range(1,N+1):
  p = N//i
  ans+=(2*i+(p-1)*i)*p//2
print(ans)

Solution (Python):
N=int(input())
ans = 0
for i in range(1,N+1):
  p = N//i
  ans+=i*(1+p)*p//2
print(ans)

Solution (Python):
n = int(input())


def f(x):
    return x * (x + 1) // 2


ans = 0
for x in range(1, n + 1):
    if x * x > n:
        break
    ans += x * x
    y_high = n // x
    ans += 2 * x * (f(y_high) - f(x))
print(ans)

Solution (Python):
n = int(input())
ret = 0
for i in range(1, n+1):
    cnt = n // i
    tt = cnt * (cnt+1) * i // 2
    ret += tt
print(ret)

Solution (Python):



import sys
from collections import defaultdict, deque
from heapq import heappush, heappop
import math
import bisect
import itertools
input = sys.stdin.readline




n = int(input())

ans = 0

for i in range(1, n+1):
    num = n // i
    last = num * i
    ans += int((i + last) * num / 2)

print(ans)

Solution (Python):

def main():
    import sys
    imput = sys.stdin.readline
    
    
    
    n = int(input())

    
    answer = n*(n+1)//2
    for i in range(2, n+1):
        for j in range(i, n+1, i):
            answer += j

    print(answer)

    
if __name__ == "__main__":
    main()

Solution (Python):
from sys import stdin,stdout
from numba import njit
@njit
def solve(n):
	fctrs=[0]*(n+1)
	ans=0
	for i in range(1,n+1):
		for j in range(i,n+1,i):
			fctrs[j]+=1
	for i in range(1,n+1):
		ans+=(i*fctrs[i])
	return ans
n=int(stdin.readline())
print(solve(n))

Solution (Python):
from numba import njit
@njit
def solve(n):
	fctrs=[0]*(n+1)
	ans=0
	for i in range(1,n+1):
		for j in range(i,n+1,i):
			fctrs[j]+=1
	for i in range(1,n+1):
		ans+=(i*fctrs[i])
	return ans
n=int(input())
print(solve(n))

Solution (Python):
mem = {}
def f(n):
	if n in mem:
		return mem[n]
	ans,b = 0, 1
	while(b <= n):
		k = n / b
		ans += b *k * (k + 1) / 2  
		b +=1
	mem[n] = ans
	return ans
print f(int(raw_input()))

Solution (Python):
def f(n):
	ans,b = 0, 1
	while(b <= n):
		k = n / b
		ans += b *k * (k + 1) / 2  
		b +=1
	return ans
print f(int(raw_input()))

Solution (Python):
n = int(input())
ans = 0
for i in range(1,n+1):
  k = n//i
  ans += i*(k*(k+1))//2
print(ans)

Solution (Python):
N = int(input())
ans = 0
for i in range(1,N+1):
    X = N//i
    ans += i*X*(X+1)//2
print(ans)

Solution (Python):
n = int(input())

def f(x):
    return x * (x + 1) // 2

ans = sum(i * f(n // i) for i in range(1, n + 1))

print(ans)

Solution (Python):
import itertools
import functools
import math
from collections import Counter
from itertools import combinations
import re


def main_chk():
    N = int(input())

    ans = 0
    for i in range(1,N+1):
        m = N // i
        ans += ( m + 1 ) * m * i / 2

    print(math.floor(ans))
main_chk()

Solution (Python):
n = int(input())
print(sum([(n//m)*((n//m)+1)*m//2 for m in range(1,n+1)]))

Solution (Python):
n = int(input())
print(sum([(n//m)*((n//m)+1)*m//2  for m in range(1,n+1)]))

Solution (Python):
n = int(input())
s = 0
for m in range(1, n+1):
    k = n // m
    s += k * (k+1) * m // 2
print(s)

Solution (Python):
n = int(input())
s = 0
for m in range(1, n+1):
    k = n // m
    s += k * (k+1) * m // 2
print(s)

Solution (Python):
def main(): 
    N=int(input())
    ANS=0
    for i in range(1,N+1):
        ANS+=i*(N//i*(N//i+1)//2)
    print(ANS)
main()

Solution (Python):
N = int(input())
ans = 0
for i in range(1, N + 1):
    x = N // i
    ans += i * x * (x + 1) // 2
print(ans)

Solution (Python):
from numba import njit
@njit("i8(i8)")

def solve(n):
  l=[1]*(n+1)
  ans=1
  for i in range(2,n+1):
    j=i
    while(j<=n):
      l[j-1]+=1
      j+=i
    ans+=(i*l[i-1])
  return ans

n=int(input())
print(solve(n))

Solution (Python):
N = int(input())
ans = 0
for i in range(1,N+1):
    ans += ((N // i) * ((N // i)+1) // 2) * i 
print(ans)

Solution (Python):
n = int(input())

res = 0
for i in range(1, n+1):
    c_n = n//i
    res += i*c_n*(c_n+1)/2

print(int(res))

Solution (Python):
import sys

def input(): return sys.stdin.readline().strip()
def list2d(a, b, c): return [[c] * b for i in range(a)]
def list3d(a, b, c, d): return [[[d] * c for j in range(b)] for i in range(a)]
def list4d(a, b, c, d, e): return [[[[e] * d for j in range(c)] for j in range(b)] for i in range(a)]
def ceil(x, y=1): return int(-(-x // y))
def INT(): return int(input())
def MAP(): return map(int, input().split())
def LIST(N=None): return list(MAP()) if N is None else [INT() for i in range(N)]
def Yes(): print('Yes')
def No(): print('No')
def YES(): print('YES')
def NO(): print('NO')
sys.setrecursionlimit(10 ** 9)
INF = 10 ** 19
MOD = 10 ** 9 + 7
EPS = 10 ** -10

def get_sum(a, d, n):
    """ 等差数列の和：(初項a, 公差d, 項数n) """
    return (2*a + (n-1)*d) * n // 2

N = INT()

ans = 0
for i in range(1, N+1):
    cnt = N // i
    ans += get_sum(i, i, cnt)
print(ans)

Solution (Python):
import math
n=int(input())
s=0
for i in range(1,n+1):
    s+=i*((math.floor(n/i)*math.floor(n/i+1))/2)
print (int(s))

Solution (Python):
n = int(input())

ans = 0
for i in range(1, n + 1):
    j = n // i
    ans += i * j * (j + 1) // 2
print(ans)

Solution (Python):

N = int(input())
ans = 0
for i in range(1, N+1):
    Y = N // i
    ans += (Y * (Y + 1)) // 2 * i
print(ans)

Solution (Python):

N = int(input())
ans = 0
for i in range(1, N+1):
    Y = N // i
    ans += (Y * (Y + 1)) // 2 * i
print(ans)

Solution (Python):
N = int(input())

counter = 0
for n in range(1,N+1):
    a = N//n
    counter += a*(a+1)*n//2


print(counter)

Solution (Python):
def main():
    N = int(input())
    ans = 0
    for i in range(1, N + 1):
        d = N // i
        ans += d * (d + 1) // 2 * i
    print(ans)

if __name__ == '__main__':
    main()

Solution (Python):
def main():
    n = int(input())
    ans = 0
 
    for i in range(1, n+1):
        y = n // i
        ans += (y+1)*y*i//2
    print(ans)
 
if __name__ == '__main__':
    main()

Solution (Python):
n = int(input())

ans = 0
for x in range(1,n+1):
    h = n//x
    ans += int(h*(h+1)/2)*x
print(ans)

Solution (Python):
def solve():
    n = int(input())
    ans = 0
    for x in range(1, n + 1):
        ans += ((n // x) * ((n // x) + 1) * x) // 2
    print(ans)






if __name__ == '__main__':
    solve()

Solution (Python):
def main():
    n = int(input())
    ans = 0
    for i in range(1, n + 1):
        m = n//i
        ans += i*m*(m+1)//2
    print(ans)


if __name__ == "__main__":
    main()

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
    k=n//i
    ans+=i*k*(k+1)//2
print(ans)

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
    k=n//i
    ans+=i*k*(k+1)//2
print(ans)

Solution (Python):



def input_int():
    return int(input())



def int1(x):
    return int(x) - 1



def input_to_int_map():
    return map(int, input().split())



def input_to_int_tuple():
    return tuple(map(int, input().split()))



def input_to_int_tuple_minus1():
    return tuple(map(int1, input().split()))


def main():
    n = input_int()

    ans = 0
    for j in range(1, n + 1):
        temp = n // j
        ans += temp * (temp + 1) * j // 2
        
        

    print(int(ans))


if __name__ == "__main__":
    main()

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
  key=n//i
  ans+=key*i*(1+key)/2
print(int(ans))

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
  num=n//i
  ans+=((num*(num+1))//2)*i
print(ans)

Solution (Python):
n=int(input())
ans=0
for i in range(1,n+1):
  num=n//i
  ans+=((num*(num+1))//2)*i
print(ans)

Solution (Python):
N = int(input())

ans = 0
for i in range(1, N + 1):
    j = N // i
    ans += i * (j * (j + 1) // 2)

print(ans)

Solution (Python):
n = int(input())

ans = int(sum([i * (n // i + 1) * (n // i) / 2 for i in range(1, n+1)]))

print(ans)

Solution (Python):
import numpy as np
 
N = int(input())
 
Xarray = np.arange(1, N+1)
Xans = ((N // Xarray) * (2 * Xarray + ((N // Xarray) - 1) * Xarray)) // 2
 
print(np.sum(Xans))