Step 1: Divide the number into separate digits:
27788 => 2 7 7 8 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 7 = 5
7 to 7 = 0
7 to 8 = 1
8 to 8 = 0
8 to 2 = 6
Step 3: Combine the filters to a string:
5 0 1 0 6 = 50106