What is the Greatest Common Factor of 840 and 860?

Greatest common factor (GCF) of 840 and 860 is 20.

GCF(840,860) = 20

We will now calculate the prime factors of 840 and 860, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 840 and 860.

How to find the GCF of 840 and 860?

We will first find the prime factorization of 840 and 860. After we will calculate the factors of 840 and 860 and find the biggest common factor number .

Step-1: Prime Factorization of 840

Prime factors of 840 are 2, 3, 5, 7. Prime factorization of 840 in exponential form is:

840 = 2³ × 3¹ × 5¹ × 7¹

Step-2: Prime Factorization of 860

Prime factors of 860 are 2, 5, 43. Prime factorization of 860 in exponential form is:

860 = 2² × 5¹ × 43¹

Step-3: Factors of 840

List of positive integer factors of 840 that divides 840 without a remainder.

1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 15, 20, 21, 24, 28, 30, 35, 40, 42, 56, 60, 70, 84, 105, 120, 140, 168, 210, 280, 420

Step-4: Factors of 860

List of positive integer factors of 860 that divides 840 without a remainder.

1, 2, 4, 5, 10, 20, 43, 86, 172, 215, 430

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 840 and 860. The biggest common factor number is the GCF number.
So the greatest common factor 840 and 860 is 20.

Also check out the Least Common Multiple of 840 and 860