Rules of Divisibility

1 divides every whole number
2
divides a whole number if it is even
3
divides a whole number if three divides the sum of the digits
4
divides a whole number if four divides the last two digits
5
divides a whole number if it ends in five or zero
6
divides a whole number if the rules for two and three above both work
7
divides a whole number if removing the digit from the ones position, doubling it, and subtracting it from the rest of the number, yields a number divisible by seven
8
divides a whole number if eight divides the last three digits
9
divides a whole number if nine divides the sum of the digits
10
divides a whole number if it ends in zero