GCF of 105 and 189 (Greatest Common Factor)

"Greatest Common Factor" Calculator
Greatest Common Factor of
and

What is the Greatest Common Divisor of 105 and 189?

Answer

GCF of 105 and 189 is
21

(Twenty-one)

Finding GCF for 105 and 189 using all factors (divisors) listing

The first method to find GCF for numbers 105 and 189 is to list all factors for both numbers and pick the highest common one:

All factors of 105: 1, 3, 5, 7, 15, 21, 35, 105

All factors of 189: 1, 3, 7, 9, 21, 27, 63, 189

So the Greatest Common Factor for 105 and 189 is 21

Finding GCF for 105 and 189 by Prime Factorization

The second method to find GCF for numbers 105 and 189 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 105: 3, 5, 7

All Prime Factors of 189: 3, 3, 3, 7

As we can see there are Prime Factors common to both numbers: 3, 7

Now we need to multiply them to find GCF: 3 × 7 = 21

See Also

About "Greatest Common Factor" Calculator

This calculator will help you find the greatest common factor (GCF) of two numbers. For example, it can help you find out what is the Greatest Common Divisor of 105 and 189? (The answer is: 21). Select the first number (e.g. '105') and the second number (e.g. '189'). After that hit the 'Calculate' button.
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder.
"Greatest Common Factor" Calculator
Greatest Common Factor of
and

GCF Table

Number 1Number 2GCF
1051743
10517535
1051761
1051773
1051781
1051791
10518015
1051811
1051827
1051833
1051841
1051855
1051863
1051871
1051881
10518921
1051905
1051911
1051923
1051931
1051941
10519515
1051967
1051971
1051983
1051991
1052005
1052013
1052021
1052037

FAQ

What is the Greatest Common Divisor of 105 and 189?

GCF of 105 and 189 is 21

How to find the GCF of 105 and 189?

You can find the GCF of 105 and 189 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 105 and 189 is 21.

What prime factors do 105 and 189 share?

The prime factorizations of 105 and 189 have 3 × 7 in common, and multiplying those shared primes gives 21 — exactly the greatest common factor.

How does the GCF reduce the fraction 105/189?

Divide the numerator and the denominator by the GCF 21: 105 ÷ 21 = 5 and 189 ÷ 21 = 9. So 105/189 in lowest terms is 5/9.