Step 1: Divide the number into separate digits:
71068 => 7 1 0 6 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 1 = 6
1 to 0 = 1
0 to 6 = 6
6 to 8 = 2
8 to 7 = 1
Step 3: Combine the filters to a string:
6 1 6 2 1 = 61621