Step 1: Divide the number into separate digits:
02605 => 0 2 6 0 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 2 = 2
2 to 6 = 4
6 to 0 = 6
0 to 5 = 5
5 to 0 = 5
Step 3: Combine the filters to a string:
2 4 6 5 5 = 24655