Step 1: Divide the number into separate digits:
22775 => 2 2 7 7 5
Step 2: Calculate the distance between each digit and the next (the last digit with the first):
2 to 2 => 0
2 to 7 => 5
7 to 7 => 0
7 to 5 => 2
5 to 2 => 3
Step 3: Convert distances to codes (0=E[qual],
1 & 9 = C[onsecutive], 2-8 = N[one]):
0 => E
5 => N
0 => E
2 => N
3 => N
Step 4: Combine the filters to a string:
E N E N N = ENENN