What is the Greatest Common Factor of 19987 and 19991?

Greatest common factor (GCF) of 19987 and 19991 is 1.

GCF(19987,19991) = 1

We will now calculate the prime factors of 19987 and 19991, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 19987 and 19991.

How to find the GCF of 19987 and 19991?

We will first find the prime factorization of 19987 and 19991. After we will calculate the factors of 19987 and 19991 and find the biggest common factor number .

Step-1: Prime Factorization of 19987

Prime factors of 19987 are 11, 23, 79. Prime factorization of 19987 in exponential form is:

19987 = 11¹ × 23¹ × 79¹

Step-2: Prime Factorization of 19991

Prime factors of 19991 are 19991. Prime factorization of 19991 in exponential form is:

19991 = 19991¹

Step-3: Factors of 19987

List of positive integer factors of 19987 that divides 19987 without a remainder.

1, 11, 23, 79, 253, 869, 1817

Step-4: Factors of 19991

List of positive integer factors of 19991 that divides 19987 without a remainder.

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 19987 and 19991. The biggest common factor number is the GCF number.
So the greatest common factor 19987 and 19991 is 1.

Also check out the Least Common Multiple of 19987 and 19991