Step 1: Divide the number into separate digits:
25116 => 2 5 1 1 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 5 = 3
5 to 1 = 4
1 to 1 = 0
1 to 6 = 5
6 to 2 = 4
Step 3: Combine the filters to a string:
3 4 0 5 4 = 34054