Step 1: Divide the number into separate digits:
78641 => 7 8 6 4 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 8 = 1
8 to 6 = 2
6 to 4 = 2
4 to 1 = 3
1 to 7 = 6
Step 3: Combine the filters to a string:
1 2 2 3 6 = 12236