Step 1: Divide the number into separate digits:
26872 => 2 6 8 7 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 6 = 4
6 to 8 = 2
8 to 7 = 1
7 to 2 = 5
2 to 2 = 0
Step 3: Combine the filters to a string:
4 2 1 5 0 = 42150