GCF (HCF) of 28 and 31

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Greatest Common Factor of
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What is the Greatest Common Divisor of 28 and 31?

Answer

GCF (HCF) of 28 and 31 is
1

Common factors: 1

Only 1 divides both: 28 and 31 share no prime factor.

Such numbers are called coprime (relatively prime); their LCM is just the product: 28 × 31 = 868.

28 = 22 × 7

31 — prime

Prime2831Lowest power
222——
77——
31—31—

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

GCF = 1

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GCF Table

Number 1Number 2GCF
28302
28311
28324
28342
28357
28364
28382
28391
28404
284214
28431
28444
28451
28462
28484
28497
28502
28511
28531
28551
285628
28604
28637
28644
287014
28724
28804
288428
289814
281057

FAQ

What is the Greatest Common Divisor of 28 and 31?

GCF (HCF) of 28 and 31 is 1

How to find the GCF of 28 and 31?

You can find the GCF of 28 and 31 by listing all factors of both numbers and picking the greatest common one, or by prime factorization. The GCF of 28 and 31 is 1.

What prime factors do 28 and 31 share?

28 and 31 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 28/31?

Divide the numerator and the denominator by the GCF 1: 28 ÷ 1 = 28 and 31 ÷ 1 = 31. So 28/31 in lowest terms is 28/31.

Are 28 and 31 coprime?

Yes, 28 and 31 are coprime (relatively prime) because their Greatest Common Factor is 1.

See Also