Step 1: Divide the number into separate digits:
70811 => 7 0 8 1 1
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 0 = 7
0 to 8 = 8
8 to 1 = 7
1 to 1 = 0
1 to 7 = 6
Step 3: Combine the filters to a string:
7 8 7 0 6 = 78706