Step 1: Divide the number into separate digits:
25673 => 2 5 6 7 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 5 = 3
5 to 6 = 1
6 to 7 = 1
7 to 3 = 4
3 to 2 = 1
Step 3: Combine the filters to a string:
3 1 1 4 1 = 31141