That's cool, but it seems like 6174 is just the unique fixed point of the Kaprekar function. Many functions have a unique fixed point so I wouldn't say this makes the number special

SimpleStacker

There is a number in mathematics that feels almost like a trick.

 you choose, as long as its digits are not all the same, you always end up in the same place.

, and once you encounter it, it is very hard to forget.

At first, it looks like a harmless numerical game. But something remarkable happens. No matter which valid number you choose, the process always leads to the same result: 

math

> There is a number in mathematics that feels almost like a trick.
>
> No matter how you start, no matter what **four-digit number** you choose, as long as its digits are not all the same, you always end up in the same place.
>
> That number is **6174**.
>
> It is known as **Kaprekar’s Constant**, and once you encounter it, it is very hard to forget.
>
> ## A simple game with numbers
>
> Let us begin with a small experiment.
>
> Take any **four-digit number**, as long as **not all digits are the same**. We allow **leading zeros**, so numbers like **0378** or **0010** are included.
>
> Rearrange the digits to form the **largest possible number**, then the **smallest** (allowing leading zeros), **subtract** the two, and **repeat**.
>
> This is known as the **Kaprekar routine**.
>
> At first, it looks like a harmless numerical game. But something remarkable happens. No matter which valid number you choose, the process always leads to the same result: **6174**.
>
> [**...read more at medium.com**](https://medium.com/think-art/the-magical-number-6174-40a8495023a5)