Step 1: Divide the number into separate digits:
69817 => 6 9 8 1 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 9 = 3
9 to 8 = 1
8 to 1 = 7
1 to 7 = 6
7 to 6 = 1
Step 3: Combine the filters to a string:
3 1 7 6 1 = 31761