# Prime Numbers

What is prime number?

Prime number – positive natural number that has 2 positive natural number divisors – one and itself.

The opposite of prime numbers are composite numbers. A composite number is a positive natural number that has at least one positive divisor other than one or itself.

The number 1 is not a prime number by definition – it has only one divisor.

The number 0 is not a prime number – it is not a positive number and has infinite number of divisors.

The number 15 has divisors of 1, 3, 5, 15 because:

15/1=15

15/3=5

15/5=3

15/15=1

So 15 is not a prime number.

The number 13 has only two divisors of 1,13.

13/1=13

13/13=1

So 13 is a prime number.

### Prime numbers list

List of prime numbers up to 100:

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, …

Is 0 a prime number?

The number 0 is not a prime number.

Zero is not a positive number and has infinite number of divisors.

Is 1 a prime number?

The number 1 is not a prime number by definition.

One is has one divisor – itself.

Is 2 a prime number?

The number 2 is a prime number.

Two has 2 natural number divisors – 1 and 2:

2 / 1 = 2

2 / 2 = 1