Step 1: Divide the number into separate digits:
72661 => 7 2 6 6 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 2 = 5
2 to 6 = 4
6 to 6 = 0
6 to 1 = 5
1 to 7 = 6
Step 3: Combine the filters to a string:
5 4 0 5 6 = 54056