Divisibility

Divisibility by 2

A number is divisible by 2 if it ends in zero or in a digit which is a multiple of 2i.e. 2,4, 6, 8.

Divisibility by 3

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

Divisibility by 4

A number is divisible by 4 if the number formed by the last two digits.

Divisibility by 5

A number is divisible by 5 if it ends in zero or 5

Divisibility by 6

A number is divisible by 6 if it divisible by 2 as well as by 3.

Divisibility by 7

Subtract 2 times the last digit from remaining truncated number. Repeat the step as necessary. If the result is divisible by 7, the original number is also divisible by 7

Divisibility by 8

A number is divisible by 8 if the number formed by the last three digits, i.e,hundreds tens and units is divisible by 8.

Divisibility by 9

A number is divisible by 9 if the sum of its digit is divisible by 9 or sum is equal to 9.

Divisibility by 10

A number is divisible by 10 if it ends in zero.

Divisibility by 11

A number is divisible by 11 if the difference between the sums of the digits in the even and odd places is zero or a multiple of 11.

Divisibility by 12

A number is divisible by 12 if it is divisible by both 4 and 3.

Divisibility by 13

Add 4 times the last digit to the remaining truncated number. Repeat the step as necessary. If the result is divisible by 13, the original number is also divisible by 13.

Divisibility by 14

If a number is divisible by 2 as well as 7

Divisibility by 15

If a number is divisible by both 3 & 5.

Divisibility by 17

Subtract 5 times the last digit from remaining truncated number. Repeat the step as necessary. If the result is divisible by 17, the original number is also divisible by 17.

Divisibility by 18

If a number is divisible by both 2 & 9.

Divisibility by 19

Add 2 times the last digit to the remaining truncated number. Repeat the step as necessary. If the result is divisible by 19, the original number is also divisible by 19.

Divisibility by 21

If a number is divisible by both 3 & 7.

Divisibility by 2

A number is divisible by 2 if it ends in zero or in a digit which is a multiple of 2i.e. 2,4, 6, 8.

Divisibility by 23

Add 7 times the last digit to the remaining truncated number. Repeat the step as necessary. If the result is divisible by 23, the original number is also divisible by 23.

Divisibility by 29

Add 3 times the last digit to the remaining truncated number. Repeat the step as necessary. If the result is divisible by 29, the original number is also divisible by 29.

Divisibility by 31

Subtract 3 times the last digit from remaining truncated number. Repeat the step as necessary. If the result is divisible by 31, the original number is also divisible by 31