Step 1: Divide the number into separate digits:
76389 => 7 6 3 8 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 6 = 1
6 to 3 = 3
3 to 8 = 5
8 to 9 = 1
9 to 7 = 2
Step 3: Combine the filters to a string:
1 3 5 1 2 = 13512