The list of prime numbers starts as follows:

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37........

All other whole numbers are known as composite and can be written as the product of prime factors.

This is known as prime factorisation.

We use indices to tidy up long strings of the **same **number.

**Examples**

54 = 2 x 3 x 3 x 3 = 2 x 3^{3}

28 = 2 x 2 x 7 = 2^{2} x 7

24 = 2 x 2 x 2 x 3 = 2^{3} x 3