Step 1: Divide the number into separate digits:
50988 => 5 0 9 8 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 0 = 5
0 to 9 = 9
9 to 8 = 1
8 to 8 = 0
8 to 5 = 3
Step 3: Combine the filters to a string:
5 9 1 0 3 = 59103