Step 1: Divide the number into separate digits:
81836 => 8 1 8 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 8 = 7
8 to 3 = 5
3 to 6 = 3
6 to 8 = 2
Step 3: Combine the filters to a string:
7 7 5 3 2 = 77532