GCF for 16, 32 and 40

"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
and

What's the Greatest Common Factor (GCF) of 16, 32 and 40?

Answer

GCF of 16, 32 and 40 is
8

(Eight)

8 is the largest positive integer that divides 16, 32 and 40 without a remainder — every other common divisor of the three divides it too.

Finding the GCF of 16, 32 and 40 by Prime Factorization

Split all three numbers into prime factors, then keep every prime that appears in all three of them, each taken as many times as it appears in the poorest factorization. Multiplying what is left gives the greatest common factor:

All Prime Factors of 16: 2 × 2 × 2 × 2 (exponent form: 24)

All Prime Factors of 32: 2 × 2 × 2 × 2 × 2 (exponent form: 25)

All Prime Factors of 40: 2 × 2 × 2 × 5 (exponent form: 23 × 5)

Prime factor163240Lowest power
224252323
55

GCF = 2 × 2 × 2 = 8

Checking the GCF of 16, 32 and 40 Two Numbers at a Time

The greatest common factor is associative, so three numbers can be handled as two pairs — and this is what makes the Euclidean algorithm usable here: run it on the first pair, then run it again on that result and the third number.

GCF(a, b, c) = GCF(GCF(a, b), c)

GCF(16, 32) = 16

GCF(16, 40) = 8

GCF(16, 32, 40) = 8

The answer checks out by division — all three quotients come out whole:

16 ÷ 8 = 2

32 ÷ 8 = 4

40 ÷ 8 = 5

2, 4 and 5 have no common factor left — that is what makes 8 the greatest one.

See Also

About "Greatest Common Factor of 3 Numbers" Calculator

This calculator finds the Greatest Common Factor (GCF) of three numbers at once, without doing it in two passes. For example, it can help you find out what's the Greatest Common Factor (GCF) of 16, 32 and 40? (The answer is: 8). Enter the first number (e.g. '16'), the second (e.g. '32') and the third (e.g. '40'), then hit the 'Calculate' button.
The Greatest Common Factor of three numbers — also called the greatest common divisor (GCD) or highest common factor (HCF) — is the largest positive integer that divides all three of them with zero remainder
"Greatest Common Factor of 3 Numbers" Calculator
Greatest Common Factor of
,
and

GCF Table

Number 1Number 2Number 3GCF
1625321
1626322
1627321
1628324
1629321
1630322
1631321
16323216
1632331
1632342
1632351
1632364
1632371
1632382
1632391
1632408
1632411
1632422
1632431
1632444
1632451
1632462
1632471
16324816
1632491
1632502
1632511
1632524
1632531
1632542

FAQ

What's the Greatest Common Factor (GCF) of 16, 32 and 40?

GCF of 16, 32 and 40 is 8

What prime factors do 16, 32 and 40 share?

All three factorizations contain 2 × 2 × 2, and multiplying those shared primes gives 8 — exactly the greatest common factor.

Can you get the GCF of 16, 32 and 40 two numbers at a time?

Yes, and it is the check this page prints. The GCF of 16 and 32 is 16, and the GCF of 16 and 40 is 8 — the same answer, because the greatest common factor is associative and does not depend on the order of the three numbers.

How does the GCF simplify the ratio 16 : 32 : 40?

Divide every term by the GCF 8: 16 ÷ 8 = 2, 32 ÷ 8 = 4 and 40 ÷ 8 = 5. So 16 : 32 : 40 in lowest terms is 2 : 4 : 5, and no whole number other than 1 divides all three of those.