Step 1: Divide the number into separate digits:
04906 => 0 4 9 0 6
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 4 = 4
4 to 9 = 5
9 to 0 = 9
0 to 6 = 6
6 to 0 = 6
Step 3: Combine the filters to a string:
4 5 9 6 6 = 45966