Step 1: Divide the number into separate digits:
89428 => 8 9 4 2 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
8 to 9 = 1
9 to 4 = 5
4 to 2 = 2
2 to 8 = 6
8 to 8 = 0
Step 3: Combine the filters to a string:
1 5 2 6 0 = 15260