|Cardinal||four hundred ninety-five|
(four hundred ninety-fifth)
|Factorization||32 × 5 × 11|
The Kaprekar's routine algorithm is defined as follows for three-digit numbers:
Repeating this process will always reach 495 in a few steps. Once 495 is reached, the process stops because 954 – 459 = 495.
For example, choose 495:
The only three-digit numbers for which this function does not work are repdigits such as 111, which give the answer 0 after a single iteration. All other three-digits numbers work if leading zeros are used to keep the number of digits at 3:
The number 6174 has the same property for the four-digit numbers.