What is the Greatest Common Factor of 21205 and 21220?

Greatest common factor (GCF) of 21205 and 21220 is 5.

GCF(21205,21220) = 5

We will now calculate the prime factors of 21205 and 21220, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 21205 and 21220.

How to find the GCF of 21205 and 21220?

We will first find the prime factorization of 21205 and 21220. After we will calculate the factors of 21205 and 21220 and find the biggest common factor number .

Step-1: Prime Factorization of 21205

Prime factors of 21205 are 5, 4241. Prime factorization of 21205 in exponential form is:

21205 = 5¹ × 4241¹

Step-2: Prime Factorization of 21220

Prime factors of 21220 are 2, 5, 1061. Prime factorization of 21220 in exponential form is:

21220 = 2² × 5¹ × 1061¹

Step-3: Factors of 21205

List of positive integer factors of 21205 that divides 21205 without a remainder.

1, 5, 4241

Step-4: Factors of 21220

List of positive integer factors of 21220 that divides 21205 without a remainder.

1, 2, 4, 5, 10, 20, 1061, 2122, 4244, 5305, 10610

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 21205 and 21220. The biggest common factor number is the GCF number.
So the greatest common factor 21205 and 21220 is 5.

Also check out the Least Common Multiple of 21205 and 21220