Step 1: Divide the number into separate digits:
4174 => 4 1 7 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 1 = 3
1 to 7 = 6
7 to 4 = 3
4 to 4 = 0
Step 3: Combine the filters to a string:
3 6 3 0 = 3630