Step 1: Divide the number into separate digits:
28058 => 2 8 0 5 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 8 = 6
8 to 0 = 8
0 to 5 = 5
5 to 8 = 3
8 to 2 = 6
Step 3: Combine the filters to a string:
6 8 5 3 6 = 68536