Number: | 495 |
495 (four hundred [and] ninety-five) is the natural number following 494 and preceding 496.
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.
The number 6174 has the same property for the four-digit numbers, albeit has a much greater percentage of workable numbers. Sometimes these numbers (495, 6174, and their counterparts in other digit lengths or in bases other than 10) are called "Peyush constants" named after Peyush Dixit who solved this routine as a part of his IMO 2000 (International Mathematical Olympiad, Year 2000) thesis. [1]