Definition of Prime Numbers

Prime Numbers

Prime Numbers - a prime number is a whole number that can be only be divided by two positive divisors, by itself and 1. The set comprises all numbers, except 1 and 0, not in the set of composite numbers.

Why isn't 1 a prime? Well because by the definition of prime the number must divisible by two positive divisors, 1 and itself. Since one is only divisible by 1 divisor it doesn't fit the definition. One is in a class of numbers called units.

Prime numbers are often used in cryptography and are an important element in computer and network security. Here is a list of prime numbers up to 10,000.