6174 - Kaprekar’s Constant
6174 is a famous 'number trick' destination: if you repeatedly rearrange and subtract digits in a 4-digit number, you usually end up at 6174.
Why this number matters
It turns abstract math into a fun puzzle anyone can run with pen and paper.
Background / history
Indian mathematician D. R. Kaprekar discovered this pattern, so 6174 is called Kaprekar’s constant.
Simple example
Start with 3524 → 5432 - 2345 = 3087 → 8730 - 0378 = 8352 → 8532 - 2358 = 6174.
Key Facts
- Reached quickly from most starting values
- Famous recreational math process
Fun fact
Most valid 4-digit starts reach 6174 within 7 steps.