GCF for 21 and 63

"Greatest Common Factor" Calculator

Greatest Common Factor of

and

What is the Greatest common Divisor of 21 and 63?

Answer: GCF of 21 and 63 is 21

(Twenty-one)

Finding GCF for 21 and 63 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 63 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 63: 1, 3, 7, 9, 21, 63

So the Greatest Common Factor for 21 and 63 is 21

Finding GCF for 21 and 63 by Prime Factorization

The second method to find GCF for numbers 21 and 63 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 63: 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

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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 63? (The answer is: 21). Select the first number (e.g. '21') and the second number (e.g. '63'). 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
6633
7637
8631
9639
10631
11631
12633
13631
14637
15633
16631
17631
18639
19631
20631
216321
22631
23631
24633
25631
26631
27639
28637
29631
30633
31631
32631
33633
34631
35637

FAQ

What is the Greatest common Divisor of 21 and 63?

GCF of 21 and 63 is 21

See Also