This What does 100 Factorial Equal? section gives an example of how large the number the factorial function can yield. 100 Factorial is a very large number and many electronic calculators are not capable of computing that large of a number.
So, What does 100 Factorial Equal?
Below is what 100 Factorial equals.
100 Factorial
Alternatively, you can write 100 factorial in scientific form as follows:
Video showing the basics of what the factorial function is: