What is the GCF of 21 and 91

"Greatest Common Factor" Calculator

What is the Greatest common Divisor of 21 and 91?

Answer: GCF of 21 and 91 is 7

(Seven)

Finding GCF for 21 and 91 using all factors (divisors) listing

The first method to find GCF for numbers 21 and 91 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 91: 1, 7, 13, 91

So the Greatest Common Factor for 21 and 91 is 7

Finding GCF for 21 and 91 by Prime Factorization

The second method to find GCF for numbers 21 and 91 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 91: 7, 13

As we can see there is only one Prime Factor common to both numbers. It is 7

So 7 is the Greatest Common Factor of 21 and 91

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 91? (The answer is: 7). Select the first number (e.g. '21') and the second number (e.g. '91'). 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

GCF Table

Number 1	Number 2	GCF
6	91	1
7	91	7
8	91	1
9	91	1
10	91	1
11	91	1
12	91	1
13	91	13
14	91	7
15	91	1
16	91	1
17	91	1
18	91	1
19	91	1
20	91	1
21	91	7
22	91	1
23	91	1
24	91	1
25	91	1
26	91	13
27	91	1
28	91	7
29	91	1
30	91	1
31	91	1
32	91	1
33	91	1
34	91	1
35	91	7

GCF for 21 and 91

"Greatest Common Factor" Calculator

What is the Greatest common Divisor of 21 and 91?

Finding GCF for 21 and 91 using all factors (divisors) listing

Finding GCF for 21 and 91 by Prime Factorization

See Also

About "Greatest Common Factor" Calculator

"Greatest Common Factor" Calculator

GCF Table

FAQ

What is the Greatest common Divisor of 21 and 91?

See Also

Number 1	Number 2	GCF
6	91	1
7	91	7
8	91	1
9	91	1
10	91	1
11	91	1
12	91	1
13	91	13
14	91	7
15	91	1
16	91	1
17	91	1
18	91	1
19	91	1
20	91	1
21	91	7
22	91	1
23	91	1
24	91	1
25	91	1
26	91	13
27	91	1
28	91	7
29	91	1
30	91	1
31	91	1
32	91	1
33	91	1
34	91	1
35	91	7

Number 1	Number 2	GCF
6	91	1
7	91	7
8	91	1
9	91	1
10	91	1
11	91	1
12	91	1
13	91	13
14	91	7
15	91	1
16	91	1
17	91	1
18	91	1
19	91	1
20	91	1
21	91	7
22	91	1
23	91	1
24	91	1
25	91	1
26	91	13
27	91	1
28	91	7
29	91	1
30	91	1
31	91	1
32	91	1
33	91	1
34	91	1
35	91	7

Number 1	Number 2	GCF
6	91	1
7	91	7
8	91	1
9	91	1
10	91	1
11	91	1
12	91	1
13	91	13
14	91	7
15	91	1
16	91	1
17	91	1
18	91	1
19	91	1
20	91	1
21	91	7
22	91	1
23	91	1
24	91	1
25	91	1
26	91	13
27	91	1
28	91	7
29	91	1
30	91	1
31	91	1
32	91	1
33	91	1
34	91	1
35	91	7