What is the Greatest Common Factor of 20990 and 21005?

Greatest common factor (GCF) of 20990 and 21005 is 5.

GCF(20990,21005) = 5

We will now calculate the prime factors of 20990 and 21005, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 20990 and 21005.

How to find the GCF of 20990 and 21005?

We will first find the prime factorization of 20990 and 21005. After we will calculate the factors of 20990 and 21005 and find the biggest common factor number .

Step-1: Prime Factorization of 20990

Prime factors of 20990 are 2, 5, 2099. Prime factorization of 20990 in exponential form is:

20990 = 2¹ × 5¹ × 2099¹

Step-2: Prime Factorization of 21005

Prime factors of 21005 are 5, 4201. Prime factorization of 21005 in exponential form is:

21005 = 5¹ × 4201¹

Step-3: Factors of 20990

List of positive integer factors of 20990 that divides 20990 without a remainder.

1, 2, 5, 10, 2099, 4198, 10495

Step-4: Factors of 21005

List of positive integer factors of 21005 that divides 20990 without a remainder.

1, 5, 4201

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 20990 and 21005. The biggest common factor number is the GCF number.
So the greatest common factor 20990 and 21005 is 5.

Also check out the Least Common Multiple of 20990 and 21005