To factor a number \(n\) is to write it as a product of prime numbers as defined below:
$$ n = \prod_{p \in P} p^{a_p} $$
Where:
- \(P\) is a Set of prime numbers
- \(p\) is a prime number
It is one of the method to determine the Greatest Common Divisor (GCD) by finding the product of common prime factors.