Step 1: Divide the number into separate digits:
98587 => 9 8 5 8 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 8 = 1
8 to 5 = 3
5 to 8 = 3
8 to 7 = 1
7 to 9 = 2
Step 3: Combine the filters to a string:
1 3 3 1 2 = 13312