Step 1: Divide the number into separate digits:
60813 => 6 0 8 1 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 0 = 6
0 to 8 = 8
8 to 1 = 7
1 to 3 = 2
3 to 6 = 3
Step 3: Combine the filters to a string:
6 8 7 2 3 = 68723