Step 1: Divide the number into separate digits:
52780 => 5 2 7 8 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 2 = 3
2 to 7 = 5
7 to 8 = 1
8 to 0 = 8
0 to 5 = 5
Step 3: Combine the filters to a string:
3 5 1 8 5 = 35185