Step 1: Divide the number into separate digits:
46597 => 4 6 5 9 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 6 = 2
6 to 5 = 1
5 to 9 = 4
9 to 7 = 2
7 to 4 = 3
Step 3: Combine the filters to a string:
2 1 4 2 3 = 21423