Step 1: Divide the number into separate digits:
33387 => 3 3 3 8 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
3 to 3 = 0
3 to 3 = 0
3 to 8 = 5
8 to 7 = 1
7 to 3 = 4
Step 3: Combine the filters to a string:
0 0 5 1 4 = 00514