Step 1: Divide the number into separate digits:
24431 => 2 4 4 3 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 4 = 2
4 to 4 = 0
4 to 3 = 1
3 to 1 = 2
1 to 2 = 1
Step 3: Combine the filters to a string:
2 0 1 2 1 = 20121