Step 1: Divide the number into separate digits:
97239 => 9 7 2 3 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
9 to 7 = 2
7 to 2 = 5
2 to 3 = 1
3 to 9 = 6
9 to 9 = 0
Step 3: Combine the filters to a string:
2 5 1 6 0 = 25160