Step 1: Divide the number into separate digits:
39273 => 3 9 2 7 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
3 to 9 = 6
9 to 2 = 7
2 to 7 = 5
7 to 3 = 4
3 to 3 = 0
Step 3: Combine the filters to a string:
6 7 5 4 0 = 67540