What is the Greatest Common Factor of 9991 and 9999?

Greatest common factor (GCF) of 9991 and 9999 is 1.

GCF(9991,9999) = 1

We will now calculate the prime factors of 9991 and 9999, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 9991 and 9999.

How to find the GCF of 9991 and 9999?

We will first find the prime factorization of 9991 and 9999. After we will calculate the factors of 9991 and 9999 and find the biggest common factor number .

Step-1: Prime Factorization of 9991

Prime factors of 9991 are 97, 103. Prime factorization of 9991 in exponential form is:

9991 = 97¹ × 103¹

Step-2: Prime Factorization of 9999

Prime factors of 9999 are 3, 11, 101. Prime factorization of 9999 in exponential form is:

9999 = 3² × 11¹ × 101¹

Step-3: Factors of 9991

List of positive integer factors of 9991 that divides 9991 without a remainder.

1, 97, 103

Step-4: Factors of 9999

List of positive integer factors of 9999 that divides 9991 without a remainder.

1, 3, 9, 11, 33, 99, 101, 303, 909, 1111, 3333

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 9991 and 9999. The biggest common factor number is the GCF number.
So the greatest common factor 9991 and 9999 is 1.

Also check out the Least Common Multiple of 9991 and 9999