Step 1: Divide the number into separate digits:
13077 => 1 3 0 7 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
1 to 3 = 2
3 to 0 = 3
0 to 7 = 7
7 to 7 = 0
7 to 1 = 6
Step 3: Combine the filters to a string:
2 3 7 0 6 = 23706