Step 1: Divide the number into separate digits:
75098 => 7 5 0 9 8
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 5 = 2
5 to 0 = 5
0 to 9 = 9
9 to 8 = 1
8 to 7 = 1
Step 3: Combine the filters to a string:
2 5 9 1 1 = 25911