Step 1: Divide the number into separate digits:
05977 => 0 5 9 7 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
0 to 5 = 5
5 to 9 = 4
9 to 7 = 2
7 to 7 = 0
7 to 0 = 7
Step 3: Combine the filters to a string:
5 4 2 0 7 = 54207