A prime number is a number that you cannot divide with anything rather than itself or 1. Examples of prime numbers are 2, 3, 5, 7, 11 and 13. When you multiply prime number, you get numbers that can be written as products of their prime factors. For instance 63, in our case, is a number gotten as a result of multiplying prime numbers. We can therefore write it as a product of its prime factors.
63 = 3 x 3 x 7
The prime numbers that make up 63 are 3 and 7, and 63 as a product of its prime factors is (3x 3 x7)
