Step 1: Divide the number into separate digits:
51496 => 5 1 4 9 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 1 = 4
1 to 4 = 3
4 to 9 = 5
9 to 6 = 3
6 to 5 = 1
Step 3: Combine the filters to a string:
4 3 5 3 1 = 43531