Step 1: Divide the number into separate digits:
24972 => 2 4 9 7 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 4 = 2
4 to 9 = 5
9 to 7 = 2
7 to 2 = 5
2 to 2 = 0
Step 3: Combine the filters to a string:
2 5 2 5 0 = 25250