GCF for 21 and 84

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

What is the Greatest common Divisor of 21 and 84?

Answer: GCF of 21 and 84 is 21

(Twenty-one)

Finding GCF for 21 and 84 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 84 is to list all factors for both numbers and pick the highest common one:

All factors of 21: 1, 3, 7, 21

All factors of 84: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84

So the Greatest Common Factor for 21 and 84 is 21

Finding GCF for 21 and 84 by Prime Factorization

The second method to find GCF for numbers 21 and 84 is to list all Prime Factors for both numbers and multiply the common ones:

All Prime Factors of 21: 3, 7

All Prime Factors of 84: 2, 2, 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

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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 21 and 84? (The answer is: 21). Select the first number (e.g. '21') and the second number (e.g. '84'). 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
6846
7847
8844
9843
10842
11841
128412
13841
148414
15843
16844
17841
18846
19841
20844
218421
22842
23841
248412
25841
26842
27843
288428
29841
30846
31841
32844
33843
34842
35847

FAQ

What is the Greatest common Divisor of 21 and 84?

GCF of 21 and 84 is 21

See Also