What is the Greatest Common Factor of 840 and 847?

Greatest common factor (GCF) of 840 and 847 is 7.

GCF(840,847) = 7

We will now calculate the prime factors of 840 and 847, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 840 and 847.

How to find the GCF of 840 and 847?

We will first find the prime factorization of 840 and 847. After we will calculate the factors of 840 and 847 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 847

Prime factors of 847 are 7, 11. Prime factorization of 847 in exponential form is:

847 = 7¹ × 11²

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 847

List of positive integer factors of 847 that divides 840 without a remainder.

1, 7, 11, 77, 121

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 840 and 847. The biggest common factor number is the GCF number.
So the greatest common factor 840 and 847 is 7.

Also check out the Least Common Multiple of 840 and 847