Step 1: Divide the number into separate digits:
82123 => 8 2 1 2 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 2 = 6
2 to 1 = 1
1 to 2 = 1
2 to 3 = 1
3 to 8 = 5
Step 3: Combine the filters to a string:
6 1 1 1 5 = 61115