Step 1: Divide the number into separate digits:
22155 => 2 2 1 5 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 2 = 0
2 to 1 = 1
1 to 5 = 4
5 to 5 = 0
5 to 2 = 3
Step 3: Combine the filters to a string:
0 1 4 0 3 = 01403