Step 1: Divide the number into separate digits:
63566 => 6 3 5 6 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 3 = 3
3 to 5 = 2
5 to 6 = 1
6 to 6 = 0
6 to 6 = 0
Step 3: Combine the filters to a string:
3 2 1 0 0 = 32100