The factorial of a natural number n, represented by **n!**, is the product of all positive integers less than or equal to n.

**n! =**n. (n-1). (n-2)… 3.2.1

## Special settings

0!=1

1!=1

The factorial of a natural number n, represented by **n!**, is the product of all positive integers less than or equal to n.

0!=1

1!=1