Question: what is the greatest common factor of the numbers 18 and 36?
Answer: Greatest Common Factor of 18 and 36. Greatest common factor (GCF) of 18 and 36 is 18. We will now calculate the prime factors of 18 and 36, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 18 and 36.