Step 1: Divide the number into separate digits:
52190 => 5 2 1 9 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 2 = 3
2 to 1 = 1
1 to 9 = 8
9 to 0 = 9
0 to 5 = 5
Step 3: Combine the filters to a string:
3 1 8 9 5 = 31895