Step 1: Divide the number into separate digits:
39772 => 3 9 7 7 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
3 to 9 = 6
9 to 7 = 2
7 to 7 = 0
7 to 2 = 5
2 to 3 = 1
Step 3: Combine the filters to a string:
6 2 0 5 1 = 62051