Exercise: Reversing a hash

Reverse a hash and discover a secret number.

I chose a secret number and this is the SHA1 hash of the number's decimal representation:

f0501dc19c8aa8925e88f6044d49555b575b65b5

HINT: The number less than 1 million.

1. You can do this exercise right here in your browser. Open the console (control-shift-j)
2. Try the number 1:

   > sha1("1")

3. NOTE: The sha1 function takes strings, not numbers