The question isn't quite right. you need to have at least 2 numbers for there to be a "common" factor.
a better question might be "what is he greatest common factor of 8 and 16?"
if your question is supposed to be "which number has 8 as it's greatest factor?" (no common)
the answer is 8 as in 8*1=8
The greatest common factor of 8 and 32 is 8.
The Greatest Common Factor (GCF) is: 8
The greatest common factor of 8 and 400 is 8.
The greatest common factor of 1624 , 8 = 8
The Greatest Common Factor (GCF) is: 8.
The Greatest Common Factor (GCF) of 8 and 68 is: 4
The GCF of 8 and 96 is 8.The Greatest Common Factor is 8
The greatest common factor of 6 and 8 is 2.
The greatest common factor of 9 , 8 = 1
The greatest common factor of 2 and 8 is 2
The greatest common factor of 8 and 417 is 1.
The greatest common factor of 78 , 8 = 2