Step 1: Divide the number into separate digits:
5737 => 5 7 3 7
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 7 = 2
7 to 3 = 4
3 to 7 = 4
7 to 5 = 2
Step 3: Combine the filters to a string:
2 4 4 2 = 2442