Step 1: Divide the number into separate digits:
62535 => 6 2 5 3 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 2 = 4
2 to 5 = 3
5 to 3 = 2
3 to 5 = 2
5 to 6 = 1
Step 3: Combine the filters to a string:
4 3 2 2 1 = 43221