# 123: The Black Hole Number

- Start with any number, say 9288759
- Count the number of even digits, the number of odd digits, the total number of digits.
- You get 347
- Repeat and you get 123
- Repeat and you get 123
- Repeat and you get 123
- …
- Once you reach 123, you never get out, just as reaching a black hole in physics implies no escape.

A simple program in Node JS to test:

Running:

I’ve read this curiosity on Gaussianos.