Step 1: Divide the number into separate digits:
75915 => 7 5 9 1 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 5 = 2
5 to 9 = 4
9 to 1 = 8
1 to 5 = 4
5 to 7 = 2
Step 3: Combine the filters to a string:
2 4 8 4 2 = 24842