Step 1: Divide the number into separate digits:
28725 => 2 8 7 2 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 8 = 6
8 to 7 = 1
7 to 2 = 5
2 to 5 = 3
5 to 2 = 3
Step 3: Combine the filters to a string:
6 1 5 3 3 = 61533