GCF for 21 and 24

What is the Greatest Common Factor of 21 and 24?

Answer: GCF of 21 and 24 is 3

(Three)

Finding GCF for 21 and 24 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 24 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 24: 1, 2, 3, 4, 6, 8, 12, 24

So the Greatest Common Factor for 21 and 24 is 3

Finding GCF for 21 and 24 by Prime Factorization

The second method to find GCF for numbers 21 and 24 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 24: 2, 2, 2, 3

As we can see there is only one Prime Factor common to both numbers. It is 3

So 3 is the Greatest Common Factor of 21 and 24

GCF Table

Number 1Number 2GCF
624
724
824
924
1024
11241
1224
13241
1424
1524
1624
1724
1824
1924
2024
2124
2224
23241
242424
25241
26242
27243
28244
29241
30246
31241
32248
33243
34242
35241

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 Factor of 21 and 24? (The answer is: 3). Select the first number (e.g. '21') and the second number (e.g. '24'). 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

FAQ

What is the Greatest Common Factor of 21 and 24?

GCF of 21 and 24 is 3