Step 1: Divide the number into separate digits:
72207 => 7 2 2 0 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 2 = 5
2 to 2 = 0
2 to 0 = 2
0 to 7 = 7
7 to 7 = 0
Step 3: Combine the filters to a string:
5 0 2 7 0 = 50270