Step 1: Divide the number into separate digits:
58191 => 5 8 1 9 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 8 = 3
8 to 1 = 7
1 to 9 = 8
9 to 1 = 8
1 to 5 = 4
Step 3: Combine the filters to a string:
3 7 8 8 4 = 37884