Step 1: Divide the number into separate digits:
25847 => 2 5 8 4 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 5 = 3
5 to 8 = 3
8 to 4 = 4
4 to 7 = 3
7 to 2 = 5
Step 3: Combine the filters to a string:
3 3 4 3 5 = 33435