Step 1: Divide the number into separate digits:
54009 => 5 4 0 0 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 4 = 1
4 to 0 = 4
0 to 0 = 0
0 to 9 = 9
9 to 5 = 4
Step 3: Combine the filters to a string:
1 4 0 9 4 = 14094