# Relative Prime, Co-Prime

## What Is A Relative Prime Also Known As A Co-Prime?

If two numbers have no common factors i.e. there Greatest Common
Factor is one, they are called relative primes; In
other words, both numbers cannot evenly divide both by the same common value. For example
the numbers 40 and 21 are called **Relative Primes** even those they
are Composite Numbers. Below is an
example:

As you can see the prime factors of 40 and 21 follow:

- 40 = 1 x 2 x 2 x 2 x 5 = 4 x 10 = 8 x 5 -> factors are 1, 2, 4, 5, 8, 40
- 21 = 1 x 3 x 7 -> factors are 1, 3, 7, and 21

**Relative-Primes**also known as

**Co-Primes**.

As you can see the prime factors of 21 and 24 follow:

- 21 = 1 x 3 x 7 -> factors are 1, 3, 7, and 21
- 24 = 1 x 2 x 3 x 4 = 3 x 8 = 4 x 6 -> factors are 1, 2, 3, 4, 6, 8, and 24