Step 1: Divide the number into separate digits:
14920 => 1 4 9 2 0
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 4 = 3
4 to 9 = 5
9 to 2 = 7
2 to 0 = 2
0 to 1 = 1
Step 3: Combine the filters to a string:
3 5 7 2 1 = 35721