Today's number is:
6174
(this number, fact and python code were submitted @amorbidobsessionwithbeauty)
Kaprekar's constant (6174) is a value to which all 4 digit numbers converge after certain operations as follows:
1. Start off with any 4 digit number with at least 2 distinct digits (even those with leading zeroes like 0024 count)
2. Make 2 numbers from it- one with the digits arranged in ascending order and the other with the digits arranged in descending order.
3. Subtract the smaller number from the greater
4. Repeat until you get 6174
It would be tedious to demonstrate it here so I wrote a simple python program for it for anyone who wants to verify this for themselves!
Additions by Wroerf:
You can see that 6174 results in itself through the following: 7641-1467=6174
There is actually an infite amount of infinite families of these numbers for different bases and digit ammounts (though not every base-length conbinations has a constant), yet 6174 is very often regarded as The Kaprekar's constant.
