Step 1: Divide the number into separate digits:
85913 => 8 5 9 1 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 5 = 3
5 to 9 = 4
9 to 1 = 8
1 to 3 = 2
3 to 8 = 5
Step 3: Combine the filters to a string:
3 4 8 2 5 = 34825