Step 1: Divide the number into separate digits:
50704 => 5 0 7 0 4
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 0 = 5
0 to 7 = 7
7 to 0 = 7
0 to 4 = 4
4 to 5 = 1
Step 3: Combine the filters to a string:
5 7 7 4 1 = 57741