What is the Greatest Common Factor of 805 and 820?

Greatest common factor (GCF) of 805 and 820 is 5.

GCF(805,820) = 5

We will now calculate the prime factors of 805 and 820, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 805 and 820.

How to find the GCF of 805 and 820?

We will first find the prime factorization of 805 and 820. After we will calculate the factors of 805 and 820 and find the biggest common factor number .

Step-1: Prime Factorization of 805

Prime factors of 805 are 5, 7, 23. Prime factorization of 805 in exponential form is:

805 = 5¹ × 7¹ × 23¹

Step-2: Prime Factorization of 820

Prime factors of 820 are 2, 5, 41. Prime factorization of 820 in exponential form is:

820 = 2² × 5¹ × 41¹

Step-3: Factors of 805

List of positive integer factors of 805 that divides 805 without a remainder.

1, 5, 7, 23, 35, 115, 161

Step-4: Factors of 820

List of positive integer factors of 820 that divides 805 without a remainder.

1, 2, 4, 5, 10, 20, 41, 82, 164, 205, 410

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 805 and 820. The biggest common factor number is the GCF number.
So the greatest common factor 805 and 820 is 5.

Also check out the Least Common Multiple of 805 and 820