Step 1: Divide the number into separate digits:
5069 => 5 0 6 9
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
5 to 0 = 5
0 to 6 = 6
6 to 9 = 3
9 to 5 = 4
Step 3: Combine the filters to a string:
5 6 3 4 = 5634