Step 1: Divide the number into separate digits:
4782 => 4 7 8 2
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
4 to 7 = 3
7 to 8 = 1
8 to 2 = 6
2 to 4 = 2
Step 3: Combine the filters to a string:
3 1 6 2 = 3162