Self Number Checker

Self Number Checker is a free online tool used to check if the number is a self number.

Self Number Checker

Eg, Is 101 a self number? Enter 101 into the input box and click Calculate button.

What is a self number?

Self number, also called as Devlali number is a natural number in a given number base b, if the natural number cannot be represented as a sum of any other natural number n and the individual digits of n. Indian mathematician D. R. Kaprekar was the first one to define these numbers.

For example, 100 is not a self number.

Because 100 can be written as

86 + 8 + 6 = 100

where n = 86.

Another example, 911 is not a self number.

Because when n = 892

892 + 8 + 9 + 2 = 911

First 100 self numbers

How to use the self number checker

The procedure to use the self number checker is as follows:

1Enter the positive integer.
2Click Calculate button to verify whether the input integer is a self number.
3Click the Reset button to start a new verification.

Solved examples using the self number checker

Example 1: Is 999 a self number?

Enter 999 into the input box and click Calculate button, as shown in the figure, 999 is not a self number.

981 + 9 + 8 + 1 = 999

Example 2: Is 2022 a self number?

Enter 2022 into the input box and click Calculate button, as shown in the figure, 2022 is a self number.

Self Number Checker