Divisibility rules

A number is divisible by 2 if its last digit is even (0, 2, 4, 6, or 8).

A number is divisible by 5 if its last digit is 0 or 5.

A number is divisible by 10 if its last digit is 0.

A number is divisible by 3 if the sum of its digits is divisible by 3.

A number is divisible by 9 if the sum of its digits is divisible by 9.

A number is divisible by 4 if the last two digits form a number that is divisible by 4.

A number is divisible by 6 if it is divisible by both 2 and 3.

A number is divisible by 8 if the last three digits form a number that is divisible by 8.

Yes, because its last digit is 0.

Yes, because the sum of its digits (1+2+3+4+5+6=21) is divisible by 3.