Step 1: Divide the number into separate digits:
77522 => 7 7 5 2 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 7 = 0
7 to 5 = 2
5 to 2 = 3
2 to 2 = 0
2 to 7 = 5
Step 3: Combine the filters to a string:
0 2 3 0 5 = 02305