Step 1: Divide the number into separate digits:
94438 => 9 4 4 3 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 4 = 5
4 to 4 = 0
4 to 3 = 1
3 to 8 = 5
8 to 9 = 1
Step 3: Combine the filters to a string:
5 0 1 5 1 = 50151