Hi what is the factorial of 21

Well now you have a new toy to play with !!

The factorial of 21 is 51,090,942,171,709,440,000 I think

$${\mathtt{21}}{!} = {\mathtt{51\,090\,942\,171\,709\,440\,000}}$$

There you go Saseflower - you are right.

To get this I used the "Calculation e.g. 1+2=3"  button from above and wrote the question in the input box.  :)

Thanks for that, Melody.....I never even thought of trying that in the "Calculation Box"