Step 1: Divide the number into separate digits:
87234 => 8 7 2 3 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 7 = 1
7 to 2 = 5
2 to 3 = 1
3 to 4 = 1
4 to 8 = 4
Step 3: Combine the filters to a string:
1 5 1 1 4 = 15114