Step 1: Divide the number into separate digits:
81936 => 8 1 9 3 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 1 = 7
1 to 9 = 8
9 to 3 = 6
3 to 6 = 3
6 to 8 = 2
Step 3: Combine the filters to a string:
7 8 6 3 2 = 78632