Step 1: Divide the number into separate digits:
44185 => 4 4 1 8 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 4 = 0
4 to 1 = 3
1 to 8 = 7
8 to 5 = 3
5 to 4 = 1
Step 3: Combine the filters to a string:
0 3 7 3 1 = 03731