Step 1: Divide the number into separate digits:
70663 => 7 0 6 6 3
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
7 to 0 => 7
0 to 6 => 6
6 to 6 => 0
6 to 3 => 3
3 to 7 => 4
Step 3: Convert distances to codes (0=E[qual],
1 & 9 = C[onsecutive], 2-8 = N[one]):
7 => N
6 => N
0 => E
3 => N
4 => N
Step 4: Combine the filters to a string:
N N E N N = NNENN