Divisibility tests
A positive integer, written in base 10, is divisible by 2 if and only if its rightmost digit is divisible by 2. A positive integer, written in base 10, is divisible by 3 if and only if the sum of its digits is divisible by 3. A positive integer, written in base 10, is divisible by 4 if and only if... Sign in to see full entry.