Step 1: Divide the number into separate digits:
28659 => 2 8 6 5 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 8 = 6
8 to 6 = 2
6 to 5 = 1
5 to 9 = 4
9 to 2 = 7
Step 3: Combine the filters to a string:
6 2 1 4 7 = 62147