Step 1: Divide the number into separate digits:
59124 => 5 9 1 2 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 9 = 4
9 to 1 = 8
1 to 2 = 1
2 to 4 = 2
4 to 5 = 1
Step 3: Combine the filters to a string:
4 8 1 2 1 = 48121