Step 1: Divide the number into separate digits:
97616 => 9 7 6 1 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 7 = 2
7 to 6 = 1
6 to 1 = 5
1 to 6 = 5
6 to 9 = 3
Step 3: Combine the filters to a string:
2 1 5 5 3 = 21553