Prime numbers

A prime number is a number which can only be divided by 1 and itself. This means that there is no other number which can divide into it such that the result is an integer.

Here are a few examples of prime numbers:
1, 2, 3, 5, 7, 11, 13, 17, 29, 31

The number 2 is the only even prime number, since all other even numbers are divisible by 2.

Very large prime numbers are used in encryption as 'keys' to secure data over networks.