Factorial

Definition

Let $n$ be a nonnegative integer. The factorial of $n$, denoted $n!$, and read as n factorial, is defined as the product of all the natural numbers from $1$ to $n$. Note that $0!$ is defined as $1$.

Behavior

Initial values

Here are the values of $n!$ for small $n=0,1,2,3,4,5,6,7$: $1,1,2,6,24,120,720,5040$.

Related notions

• Primorial is the product of the first few primes.