Factorial n! of a positive integer n is defined as:
The special case 0! is defined to have a value of 1: 0! = 1
This calculator below can calculate ANY factorial you want (unless you run out of computer memory to hold the resulting number) if you are willing to wait. So, go on, enter the positive integer and wait for the result. Note that you can stop the calculation at any time.
Yeah, I know, big integers will be included in ES2020, but not yet, so we rely on an external library. And, with a big integers library, you are practically unlimited. Of course, there are a couple of caveats, like you have to compute factorial iteratively; otherwise, you run out of the stack, but technically, you are limited only by the time you are willing to wait until calculation completes.