Step 1: Divide the number into separate digits:
01797 => 0 1 7 9 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 1 = 1
1 to 7 = 6
7 to 9 = 2
9 to 7 = 2
7 to 0 = 7
Step 3: Combine the filters to a string:
1 6 2 2 7 = 16227