Step 1: Divide the number into separate digits:
46729 => 4 6 7 2 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 6 = 2
6 to 7 = 1
7 to 2 = 5
2 to 9 = 7
9 to 4 = 5
Step 3: Combine the filters to a string:
2 1 5 7 5 = 21575