GCF (HCF) of 2 and 21

"Greatest Common Factor" Calculator

What is the Greatest Common Divisor of 2 and 21?

Answer

GCF (HCF) of 2 and 21 is

Common factors: 1

Only 1 divides both: 2 and 21 share no prime factor.

Such numbers are called coprime (relatively prime); their LCM is just the product: 2 × 21 = 42.

2 — prime

21 = 3 × 7

Prime	2	21	Lowest power
2	2	—	—
3	—	3	—
7	—	7	—

— = power 0: the prime is not a factor of this number, so it cannot be in the GCF.

GCF = 1

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Related Calculations

GCF Table

Number 1	Number 2	GCF
2	1	1
2	3	1
2	4	2
2	5	1
2	6	2
2	7	1
2	8	2
2	9	1
2	10	2
2	12	2
2	13	1
2	14	2
2	15	1
2	18	2
2	20	2
2	21	1
2	22	2
2	24	2
2	25	1
2	26	2
2	27	1
2	28	2
2	30	2
2	31	1
2	34	2
2	36	2
2	41	1
2	43	1
2	48	2
2	49	1

FAQ

What is the Greatest Common Divisor of 2 and 21?

GCF (HCF) of 2 and 21 is 1

How to find the GCF of 2 and 21?

You can find the GCF of 2 and 21 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 2 and 21 is 1.

What prime factors do 2 and 21 share?

2 and 21 have no prime factor in common, so the only integer that divides both of them is 1 and their GCF is 1.

How does the GCF reduce the fraction 2/21?

Divide the numerator and the denominator by the GCF 1: 2 ÷ 1 = 2 and 21 ÷ 1 = 21. So 2/21 in lowest terms is 2/21.

Are 2 and 21 coprime?

Yes, 2 and 21 are coprime (relatively prime) because their Greatest Common Factor is 1.

GCF (HCF) of 2 and 21

What is the Greatest Common Divisor of 2 and 21?

More with these numbers

Related Calculations

See Also

GCF Table

FAQ

What is the Greatest Common Divisor of 2 and 21?

How to find the GCF of 2 and 21?

What prime factors do 2 and 21 share?

How does the GCF reduce the fraction 2/21?

Are 2 and 21 coprime?

See Also

Number 1	Number 2	GCF
2	1	1
2	3	1
2	4	2
2	5	1
2	6	2
2	7	1
2	8	2
2	9	1
2	10	2
2	12	2
2	13	1
2	14	2
2	15	1
2	18	2
2	20	2
2	21	1
2	22	2
2	24	2
2	25	1
2	26	2
2	27	1
2	28	2
2	30	2
2	31	1
2	34	2
2	36	2
2	41	1
2	43	1
2	48	2
2	49	1

Number 1	Number 2	GCF
2	1	1
2	3	1
2	4	2
2	5	1
2	6	2
2	7	1
2	8	2
2	9	1
2	10	2
2	12	2
2	13	1
2	14	2
2	15	1
2	18	2
2	20	2
2	21	1
2	22	2
2	24	2
2	25	1
2	26	2
2	27	1
2	28	2
2	30	2
2	31	1
2	34	2
2	36	2
2	41	1
2	43	1
2	48	2
2	49	1

Number 1	Number 2	GCF
2	1	1
2	3	1
2	4	2
2	5	1
2	6	2
2	7	1
2	8	2
2	9	1
2	10	2
2	12	2
2	13	1
2	14	2
2	15	1
2	18	2
2	20	2
2	21	1
2	22	2
2	24	2
2	25	1
2	26	2
2	27	1
2	28	2
2	30	2
2	31	1
2	34	2
2	36	2
2	41	1
2	43	1
2	48	2
2	49	1