Question

Check whether the no. 21^n can end with digit 0 or not for any natural no.
I

Answer 1

Given,

=  21^n

= ( 3 * 7 ) ^ n

= 3^n * 7^n

For any number to end with 0 it should be in the form of 2^m * 5^n, but here it is not so.Hence,21^n can't end with 0.

Answer 2

this no. could not end with 0 since it has no common factor 5
${21}^{n} = {7}^{ n } \times {3}^{n}$