Step 1: Divide the number into separate digits:
61111 => 6 1 1 1 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
6 to 1 = 5
1 to 1 = 0
1 to 1 = 0
1 to 1 = 0
1 to 6 = 5
Step 3: Combine the filters to a string:
5 0 0 0 5 = 50005