Question

What is the factorial of $20$?

Answer 1

Determine the factorial of $20$.

$n!$ represents the factorial $n$.

Such that, $\mathit{n}\mathbf{!}\mathbf{=}\mathit{n}\left(n-1\right)\left(n-2\right)\mathbf{\dots }\mathbf{\dots }\mathbf{\dots }\left(3\right)\left(2\right)\left(1\right)$

Calculate the factorial of $20$:

$\begin{array}{rcl}20!& =& 20\times 19\times 18\times 17\times 16\times 15\times 14\times \dots \dots \times 3\times 2\times 1\\ & \Rightarrow & 20!=2432902008176640000\end{array}$

Hence, the required factorial is $20!=\begin{array}{l}2432902008176640000\end{array}$.