What is the Greatest Common Factor of 19985 and 19990?

Greatest common factor (GCF) of 19985 and 19990 is 5.

GCF(19985,19990) = 5

We will now calculate the prime factors of 19985 and 19990, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 19985 and 19990.

How to find the GCF of 19985 and 19990?

We will first find the prime factorization of 19985 and 19990. After we will calculate the factors of 19985 and 19990 and find the biggest common factor number .

Step-1: Prime Factorization of 19985

Prime factors of 19985 are 5, 7, 571. Prime factorization of 19985 in exponential form is:

19985 = 5¹ × 7¹ × 571¹

Step-2: Prime Factorization of 19990

Prime factors of 19990 are 2, 5, 1999. Prime factorization of 19990 in exponential form is:

19990 = 2¹ × 5¹ × 1999¹

Step-3: Factors of 19985

List of positive integer factors of 19985 that divides 19985 without a remainder.

1, 5, 7, 35, 571, 2855, 3997

Step-4: Factors of 19990

List of positive integer factors of 19990 that divides 19985 without a remainder.

1, 2, 5, 10, 1999, 3998, 9995

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 19985 and 19990. The biggest common factor number is the GCF number.
So the greatest common factor 19985 and 19990 is 5.

Also check out the Least Common Multiple of 19985 and 19990