GCF (HCF) of 45 and 81

"Greatest Common Factor" Calculator

What is the Greatest Common Divisor of 45 and 81?

Answer

GCF (HCF) of 45 and 81 is

Common factors: 1, 3, 9

9 divides both: 45 ÷ 9 = 5, 81 ÷ 9 = 9 — and 5 and 9 share no factor but 1, so no larger number divides both.

45 = 3² × 5

81 = 3⁴

Prime	45	81	Lowest power
3	3²	3⁴	3²
5	5	—	—

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

GCF = 3² = 9

More with these numbers

Related Calculations

GCF Table

Number 1	Number 2	GCF
45	48	3
45	49	1
45	50	5
45	51	3
45	52	1
45	54	9
45	55	5
45	56	1
45	60	15
45	63	9
45	65	5
45	70	5
45	72	9
45	75	15
45	76	1
45	80	5
45	81	9
45	90	45
45	95	5
45	99	9
45	100	5
45	105	15
45	108	9
45	117	9
45	120	15
45	125	5
45	135	45
45	150	15
45	180	45
45	405	45

FAQ

What is the Greatest Common Divisor of 45 and 81?

GCF (HCF) of 45 and 81 is 9

How to find the GCF of 45 and 81?

You can find the GCF of 45 and 81 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 45 and 81 is 9.

What prime factors do 45 and 81 share?

The prime factorizations of 45 and 81 have 3 × 3 in common, and multiplying those shared primes gives 9 — exactly the greatest common factor.

How does the GCF reduce the fraction 45/81?

Divide the numerator and the denominator by the GCF 9: 45 ÷ 9 = 5 and 81 ÷ 9 = 9. So 45/81 in lowest terms is 5/9.

GCF (HCF) of 45 and 81

What is the Greatest Common Divisor of 45 and 81?

More with these numbers

Related Calculations

See Also

GCF Table

FAQ

What is the Greatest Common Divisor of 45 and 81?

How to find the GCF of 45 and 81?

What prime factors do 45 and 81 share?

How does the GCF reduce the fraction 45/81?

See Also

Number 1	Number 2	GCF
45	48	3
45	49	1
45	50	5
45	51	3
45	52	1
45	54	9
45	55	5
45	56	1
45	60	15
45	63	9
45	65	5
45	70	5
45	72	9
45	75	15
45	76	1
45	80	5
45	81	9
45	90	45
45	95	5
45	99	9
45	100	5
45	105	15
45	108	9
45	117	9
45	120	15
45	125	5
45	135	45
45	150	15
45	180	45
45	405	45

Number 1	Number 2	GCF
45	48	3
45	49	1
45	50	5
45	51	3
45	52	1
45	54	9
45	55	5
45	56	1
45	60	15
45	63	9
45	65	5
45	70	5
45	72	9
45	75	15
45	76	1
45	80	5
45	81	9
45	90	45
45	95	5
45	99	9
45	100	5
45	105	15
45	108	9
45	117	9
45	120	15
45	125	5
45	135	45
45	150	15
45	180	45
45	405	45

Number 1	Number 2	GCF
45	48	3
45	49	1
45	50	5
45	51	3
45	52	1
45	54	9
45	55	5
45	56	1
45	60	15
45	63	9
45	65	5
45	70	5
45	72	9
45	75	15
45	76	1
45	80	5
45	81	9
45	90	45
45	95	5
45	99	9
45	100	5
45	105	15
45	108	9
45	117	9
45	120	15
45	125	5
45	135	45
45	150	15
45	180	45
45	405	45