The factorial of n is equal to .

n! = n*(n-1)*(n-2)*(n-3)* ... *2*1

Explanation:

The factorial operator is simply a mathematical expression of the product of a stated integer and all integers below that number down to 1.  Consider these following examples:

4! = 4 * 3 * 2 * 1

4! = 12 * 2 * 1

4! = 24

6! = 6 * 5 * 4 * 3 * 2 * 1

6! = 30 * 4 * 3 * 2 * 1

6! = 120 * 3 * 2 * 1

6! = 360 * 2 * 1

6! = 720

So, the factorial of n would follow the same as such:

n! = n * (n-1) * (n-2) * ... * 2 * 1

Cheers.