Step 1: Divide the number into separate digits:
98612 => 9 8 6 1 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 8 = 1
8 to 6 = 2
6 to 1 = 5
1 to 2 = 1
2 to 9 = 7
Step 3: Combine the filters to a string:
1 2 5 1 7 = 12517