2

2 is the first prime number. It's the only even prime number, as all larger even numbers are divisible by 2, making them composite. Furthermore, it's the only prime number that's spelled without the letter “e” and the only prime number with the ordinal number spelled without the letter “t”.
==Proofs==
*
*
*Therefore it only has two factors.
Every even number is divisible by 2. Therefore, the only even prime is 2 because all larger even numbers will be divisible by at least three factors - itself, 2 and 1.
==Unique Properties==
*2 is the only prime number without an "e" in its name. This is because 2 is the only even prime number and all odd numbers have an e in their name.
*Even numbers are all divisible by 2.
*2+2=2\times2=2^2
*\sum_{k=1}^\infty\frac{1}{k^2} \not= 2
*\sum_{k=0}^\infty\frac{1}{2^k} = 2
==As an Exponent of Mersenne Number==
2^2-1, which is the number 3, is a prime number. It's the 1st Mersenne Prime.
==Relationship with other numbers==
===The numbers before===
*All negative numbers are not prime numbers, because they are divisible by both negative and positive factors.
*0 is not a prime number, because by definition, 0 has an infinite amount of factors, so 0 is not a prime number.
*1 is not a prime number, because it only has 1 factor, itself, prime numbers has 2 factors, 1 and itself, e.g. 2,3,5,7,11, so 1 is not a prime number.
===The numbers after===
*The next odd number, 3, is a prime number.
*4 is the first composite number, with 3 factors, 1, 2 and itself (4).
*5, the odd number following 3, is a prime number.
==Usage==
===Science===
*2 is the atomic number of helium, meaning that there are two protons and electrons in a helium atom. There are also two neutrons in helium-4, the most common isotope of helium.
*There are two electrons in the first full electron shell of an atom.
*Group two elements are alkaline earth metals. They have a valency of 2.
*Deuterium, an isotope of hydrogen, has an atomic mass of two.
===Technology===
*2 is the resin identification code used in recycling to identify high-density polyethylene.
===Sports===
*In basketball, any shot not outside the three-point field goal is equal to two points, unless the player who threw the ball is fouled while attempting the shot.
*In Association football (soccer), the scoring of two goals by one individual in a single match is referred to as a brace.
*In American football, the scoring of two points is called a safety, which can be obtained by sacking the quarterback from the goal line to the 5 yard line. Sacking the quarterback makes the line of scrimmage 6 yards back, putting the line of scrimmage into the end zone. The defensive team gains to points.
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02
0002
Category:1-Digit Prime Numbers
Category:Additive Primes
Category:Circular Primes
Category:Fibonacci Primes
Category:Factorial Primes
Category:Palindromic Primes
Category:Chen Primes
Category:Eban Primes
Category:Nban Primes
Category:Iccanobif Primes
Category:Euler’s Number Primes
Category:Right trunctable primes
Category:Even digit primes
Category:Consecutive Prime Numbers
Category:Bell primes