I'm not sure you've given us enough information. Every nonzero integer can be a factor, so unless you have a specific number in mind, your answer is potentially any nonzero number except 11.
11
No, 11 is a factor of 891.
No, 11 is a factor of 22. 22 is a multiple of 11.
1,3,9 thats all GO LAKERS!
11 is a factor of 5907.
11 is a factor of 11. It's also a factor of 121. So 11 must be the greatest factor that's common to both 11 and 121. If there were a greater one, then there would have to be a factor of 11 that's greater than 11, which would not be easy.
Since 11 is a factor of 33, it is automatically the GCF.
11 is not a factor of 111.
11 is not a factor of 111.
11 is not a factor of 111.
3 is not a prime factor of 11.
That's not an either/or. 11 is prime and it can be a factor.