# 900 (number)

900 (nine hundred) is the natural number following 899 and preceding 901. It is the square of 30 and the sum of Euler's totient function for the first 54 positive integers. In base 10, it is a Harshad number. It is also the first number to be the square of a sphenic number.

## In other fields

900 is also:
* A telephone area code for "premium" telephone calls in the North American Numbering Plan (900 number)
* In Greek number symbols, the sign Sampi ("ϡ", literally "like a pi")
* A skateboarding trick in which the skateboarder spins two and a half times (360 degrees times 2.5 is 900)
* A 900 series refers to three consecutive perfect games in bowling
* Yoda's age in Star Wars

## Integers from 901 to 999
### 900s

* 901 = 17 × 53, centered triangular number, happy number
* 902 = 2 × 11 × 41, sphenic number, nontotient, Harshad number
* 903 = 3 × 7 × 43, sphenic number, 42nd triangular number, Schröder–Hipparchus number, Mertens function(903) returns 0, little Schroeder number
* 904 = 2$^3$ × 113 or 113 × 8, refactorable number, Mertens function(904) returns 0, lazy caterer number, number of 1's in all partitions of 26 into odd parts
* 905 = 5 × 181, sum of seven consecutive primes (109 + 113 + 127 + 131 + 137 + 139 + 149), smallest composite de Polignac number
** "The 905" is a common nickname for the suburban portions of the Greater Toronto Area in Canada, a region whose telephones used area code 905 before overlay plans added two more area codes.
* 906 = 2 × 3 × 151, strobogrammatic, sphenic number, Mertens function(906) returns 0
* 907 = prime number
* 908 = 2$^2$ × 227, nontotient, number of primitive sorting networks on 6 elements, number of rhombic tilings of a 12-gon
* 909 = 3$^2$ × 101, number of non-isomorphic aperiodic multiset partitions of weight 7

### 910s

* 910 = 2 × 5 × 7 × 13, Mertens function(910) returns 0, Harshad number, happy number, balanced number, number of polynomial symmetric functions of matrix of order 7 under separate row and column permutations
* 911 = Sophie Germain prime number, also the emergency telephone number in North America
* 912 = 2$^4$ × 3 × 19, sum of four consecutive primes (223 + 227 + 229 + 233), sum of ten consecutive primes (71 + 73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109), Harshad number.
* 913 = 11 × 83, Smith number, Mertens function(913) returns 0.
* 914 = 2 × 457, nontotient, number of compositions of 11 that are neither weakly increasing nor weakly decreasing
* 915 = 3 × 5 × 61, sphenic number, Smith number, Mertens function(915) returns 0, Harshad number
* 916 = 2$^2$ × 229, Mertens function(916) returns 0, nontotient, strobogrammatic, member of the Mian–Chowla sequence
* 917 = 7 × 131, sum of five consecutive primes (173 + 179 + 181 + 191 + 193)
* 918 = 2 × 3$^3$ × 17, Harshad number
* 919 = prime number, cuban prime, prime index prime, Chen prime, palindromic prime, centered hexagonal number, Mertens function(919) returns 0

### 920s

* 920 = 2$^3$ × 5 × 23, Mertens function(920) returns 0, total number of nodes in all rooted trees with 8 nodes
* 921 = 3 × 307, number of enriched r-trees of size 7
* 922 = 2 × 461, nontotient, Smith number
* 923 = 13 × 71, number of combinations of 6 things from 1 to 6 at a time
* 924 = 2$^2$ × 3 × 7 × 11, sum of a twin prime (461 + 463), central binomial coefficient ${\tbinom {12}{6}}$
* 925 = 5$^2$ × 37, pentagonal number, centered square number
** The millesimal fineness number for Sterling silver
* 926 = 2 × 463, sum of six consecutive primes (139 + 149 + 151 + 157 + 163 + 167), nontotient
* 927 = 3$^2$ × 103, tribonacci number
* 928 = 2$^5$ × 29, sum of four consecutive primes (227 + 229 + 233 + 239), sum of eight consecutive primes (101 + 103 + 107 + 109 + 113 + 127 + 131 + 137), happy number
* 929 = prime number, Proth prime, palindromic prime, sum of nine consecutive primes (83 + 89 + 97 + 101 + 103 + 107 + 109 + 113 + 127), Eisenstein prime with no imaginary part
** An area code in New York.

### 930s

* 930 = 2 × 3 × 5 × 31, pronic number
* 931 = 7$^2$ × 19; sum of three consecutive primes (307 + 311 + 313); double repdigit, 111$_{30}$ and 777$_{11}$; number of regular simple graphs spanning 7 vertices
* 932 = 2$^2$ × 233, number of regular simple graphs on 7 labeled nodes
* 933 = 3 × 311
* 934 = 2 × 467, nontotient
* 935 = 5 × 11 × 17, sphenic number, Lucas–Carmichael number, Harshad number
* 936 = 2$^3$ × 3$^2$ × 13, pentagonal pyramidal number, Harshad number
* 937 = prime number, Chen prime, star number, happy number
* 938 = 2 × 7 × 67, sphenic number, nontotient, number of lines through at least 2 points of an 8 × 8 grid of points
* 939 = 3 × 313, number of V-toothpicks after 31 rounds of the honeycomb sequence

### 940s

* 940 = 2$^2$ × 5 × 47, totient sum for first 55 integers
* 941 = prime number, sum of three consecutive primes (311 + 313 + 317), sum of five consecutive primes (179 + 181 + 191 + 193 + 197), Chen prime, Eisenstein prime with no imaginary part
* 942 = 2 × 3 × 157, sphenic number, sum of four consecutive primes (229 + 233 + 239 + 241), nontotient, convolved Fibonacci number
* 943 = 23 × 41
* 944 = 2$^4$ × 59, nontotient, Lehmer-Comtet number
* 945 = 3$^3$ × 5 × 7, double factorial of 9, smallest odd abundant number (proper divisors add up to more than 975); smallest odd primitive abundant number; smallest odd primitive semiperfect number; Leyland number
* 946 = 2 × 11 × 43, sphenic number, 43rd triangular number, hexagonal number, happy number
* 947 = prime number, sum of seven consecutive primes (113 + 127 + 131 + 137 + 139 + 149 + 151), balanced prime, Chen prime, lazy caterer number, Eisenstein prime with no imaginary part
* 948 = 2$^2$ × 3 × 79, nontotient, forms a Ruth–Aaron pair with 949 under second definition, number of combinatory separations of normal multisets of weight 6.
* 949 = 13 × 73, forms a Ruth–Aaron pair with 948 under second definition

### 950s

* 950 = 2 × 5$^2$ × 19, nontotient, generalized pentagonal number
** one of two ISBN Group Identifiers for books published in Argentina
* 951 = 3 × 317, centered pentagonal number
** one of two ISBN Group Identifiers for books published in Finland
* 952 = 2$^3$ × 7 × 17, number of reduced words of length 3 in the Weyl group D_17, number of regions in regular tetradecagon with all diagonals drawn.
** 952 is also 9-5-2, a card game similar to bridge.
** one of two ISBN Group Identifiers for books published in Finland
* 953 = prime number, Sophie Germain prime, Chen prime, Eisenstein prime with no imaginary part, centered heptagonal number
** ISBN Group Identifier for books published in Croatia
* 954 = 2 × 3$^2$ × 53, sum of ten consecutive primes (73 + 79 + 83 + 89 + 97 + 101 + 103 + 107 + 109 + 113), nontotient, Harshad number, sixth derivative of x^(x^x) at x=1.
** ISBN Group Identifier for books published in Bulgaria. Also one of the Area Codes in the South Florida Area
* 955 = 5 × 191, number of transitive rooted trees with 17 nodes
** ISBN Group Identifier for books published in Sri Lanka
* 956 = 2$^2$ × 239, number of compositions of 13 into powers of 2.
** ISBN Group Identifier for books published in Chile
* 957 = 3 × 11 × 29, sphenic number, antisigma(45)
** one of two ISBN Group Identifiers for books published in Taiwan and China
* 958 = 2 × 479, nontotient, Smith number
** ISBN Group Identifier for books published in Colombia
** The millesimal fineness number for Britannia silver
* 959 = 7 × 137, composite de Polignac number
** ISBN Group Identifier for books published in Cuba

### 960s

* 960 = 2$^6$ × 3 × 5, sum of six consecutive primes (149 + 151 + 157 + 163 + 167 + 173), Harshad number
** country calling code for Maldives, ISBN Group Identifier for books published in Greece
** The number of possible starting positions for the chess variant Chess960
* 961 = 31$^2$, the largest 3-digit perfect square, sum of three consecutive primes (313 + 317 + 331), sum of five consecutive primes (181 + 191 + 193 + 197 + 199), centered octagonal number
** country calling code for Lebanon, ISBN Group Identifier for books published in Slovenia
* 962 = 2 × 13 × 37, sphenic number, nontotient
** country calling code for Jordan, one of two ISBN Group Identifiers for books published in Hong Kong
* 963 = 3$^2$ × 107, sum of the first twenty-four primes
** country calling code for Syria, ISBN Group Identifier for books published in Hungary
* 964 = 2$^2$ × 241, sum of four consecutive primes (233 + 239 + 241 + 251), nontotient, totient sum for first 56 integers
** country calling code for Iraq, ISBN Group Identifier for books published in Iran, happy number
* 965 = 5 × 193
** country calling code for Kuwait, ISBN Group Identifier for books published in Israel
* 966 = 2 × 3 × 7 × 23 = $\left\{{8 \atop 3}\right\}$, sum of eight consecutive primes (103 + 107 + 109 + 113 + 127 + 131 + 137 + 139), Harshad number
** country calling code for Saudi Arabia, one of two ISBN Group Identifiers for books published in Ukraine
* 967 = prime number, prime index prime
** country calling code for Yemen, one of two ISBN Group Identifiers for books published in Malaysia
* 968 = 2$^3$ × 11$^2$, nontotient, Achilles number, area of a square with diagonal 44
** country calling code for Oman, one of two ISBN Group Identifiers for books published in Mexico
* 969 = 3 × 17 × 19, sphenic number, nonagonal number, tetrahedral number
** ISBN Group Identifier for books published in Pakistan, age of Methuselah according to Old Testament, anti-Muslim movement in Myanmar

### 970s

* 970 = 2 × 5 × 97, sphenic number, heptagonal number
** country calling code for Palestinian territories, one of two ISBN Group Identifiers for books published in Mexico
* 971 = prime number, Chen prime, Eisenstein prime with no imaginary part
** country calling code for United Arab Emirates, ISBN Group Identifier for books published in the Philippines
* 972 = 2$^2$ × 3$^5$, Harshad number, Achilles number
** country calling code for Israel, one of two ISBN Group Identifiers for books published in Portugal
*** The Sum of Anti-Factors of 972 = number * (n/2) where n is an Odd number. So, it is a Hemi-Anti-Perfect Number. Other such Numbers include 2692, etc.
972 has Anti-Factors = 5, 8, 24, 29, 67, 72, 216, 389, 648
Sum of Anti-Factors = 5 + 8 + 24 + 29 + 67 + 72 + 216 + 389 + 648 = 1458 = 972 * 3/2
* 973 = 7 × 139, happy number
** country calling code for Bahrain, ISBN Group Identifier for books published in Romania,
* 974 = 2 × 487, nontotient, 974! - 1 is prime
** country calling code for Qatar, ISBN Group Identifier for books published in Thailand
* 975 = 3 × 5$^2$ × 13
** country calling code for Bhutan, ISBN Group Identifier for books published in Turkey
* 976 = 2$^4$ × 61, decagonal number
** country calling code for Mongolia, ISBN Group Identifier for books published in Antigua, Bahamas, Barbados, Belize, Cayman Islands, Dominica, Grenada, Guyana, Jamaica, Montserrat, Saint Kitts and Nevis, St. Lucia, St. Vincent and the Grenadines, Trinidad and Tobago, and the British Virgin Islands
* 977 = prime number, sum of nine consecutive primes (89 + 97 + 101 + 103 + 107 + 109 + 113 + 127 + 131), balanced prime, Chen prime, Eisenstein prime with no imaginary part, Stern prime, strictly non-palindromic number
** country calling code for Nepal
** EAN prefix for ISSNs
** ISBN Group Identifier for books published in Egypt
* 978 = 2 × 3 × 163, sphenic number, nontotient, number of secondary structures of RNA molecules with 11 nucleotides
** First EAN prefix for ISBNs
** ISBN Group Identifier for books published in Nigeria
* 979 = 11 × 89, the sum of the five smallest fourth powers: $979=\sum _{n=1}^{5}n^{4}$
** Second EAN prefix for ISBNs. Also for ISMNs
** ISBN Group Identifier for books published in Indonesia

### 980s

* 980 = 2$^2$ × 5 × 7$^2$, number of ways to tile a hexagon of edge 3 with calissons of side 1.
** ISBN Group Identifier for books published in Venezuela
* 981 = 3$^2$ × 109
** one of two ISBN Group Identifiers for books published in Singapore
* 982 = 2 × 491, happy number
** ISBN Group Identifier for books published in the Cook Islands, Fiji, Kiribati, Marshall Islands, Micronesia, Nauru, New Caledonia, Niue, Palau, Solomon Islands, Tokelau, Tonga, Tuvalu, Vanuatu, Western Samoa
* 983 = prime number, safe prime, Chen prime, Eisenstein prime with no imaginary part, Wedderburn–Etherington number, strictly non-palindromic number
** One of two ISBN Group Identifiers for books published in Malaysia
* 984 = 2$^3$ × 3 × 41
** ISBN Group Identifier for books published in Bangladesh
* 985 = 5 × 197, sum of three consecutive primes (317 + 331 + 337), Markov number, Pell number, Smith number
** one of two ISBN Group Identifiers for books published in Belarus
* 986 = 2 × 17 × 29, sphenic number, nontotient, strobogrammatic, number of unimodal compositions of 14 where the maximal part appears once
** one of two ISBN Group Identifiers for books published in Taiwan and China
* 987 = 3 × 7 × 47, sphenic number, Fibonacci number, number of partitions of 52 into prime parts
** one of two ISBN Group Identifiers for books published in Argentina
* 988 = 2$^2$ × 13 × 19, nontotient. sum of four consecutive primes (239 + 241 + 251 + 257). A cake number.
** one of two ISBN Group Identifiers for books published in Hong Kong.
* 989 = 23 × 43, Extra strong Lucas pseudoprime
** one of two ISBN Group Identifiers for books published in Portugal

### 990s

* 990 = 2 × 3$^2$ × 5 × 11, sum of six consecutive primes (151 + 157 + 163 + 167 + 173 + 179), 44th triangular number, Harshad number
** best possible VantageScore credit score
* 991 = prime number, sum of five consecutive primes (191 + 193 + 197 + 199 + 211), sum of seven consecutive primes (127 + 131 + 137 + 139 + 149 + 151 + 157), Chen prime, lucky prime, prime index prime
* 992 = 2$^5$ × 31, pronic number, nontotient; number of eleven-dimensional exotic spheres.
** country calling code for Tajikistan
* 993 = 3 × 331
** country calling code for Turkmenistan
* 994 = 2 × 7 × 71, sphenic number, nontotient, number of binary words of length 13 with all distinct runs.
** country calling code for Azerbaijan
* 995 = 5 × 199
** country calling code for Georgia
** Singapore fire brigade and emergency ambulance services hotline, Brunei Darussalam fire service emergency number
* 996 = 2$^2$ × 3 × 83
** country calling code for Kyrgyzstan
* 997 = largest three-digit prime number, strictly non-palindromic number. It is also a lucky prime.
* 998 = 2 × 499, nontotient, number of 7-node graphs with two connected components.
** country calling code for Uzbekistan
* 999 = 3$^3$ × 37, Kaprekar number, Harshad number
** In some parts of the world, such as the UK and Commonwealth countries, 999 (pronounced as nine, nine, nine) is the emergency telephone number for all emergency services
** 999 was a London punk band active during the 1970s.