Step 1: Divide the number into separate digits:
56620 => 5 6 6 2 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 6 = 1
6 to 6 = 0
6 to 2 = 4
2 to 0 = 2
0 to 5 = 5
Step 3: Combine the filters to a string:
1 0 4 2 5 = 10425