What is the GCF of 26 and 40?

The greatest common factor of 26 and 40 is 2.

What is the LCM of 26 and 40?

The least common multiple of 26 and 40 is 520.

Are 26 and 40 coprime?

No. They share the common factor 2, and their GCF is 2.

GCF and LCM of 26 and 40

The GCF of 26 and 40 is 2. The LCM of 26 and 40 is 520.

GCF (greatest common factor, also called GCD or HCF) of 26 and 40 = 2
LCM (least common multiple) of 26 and 40 = 520

Method 1: list the factors (GCF)

Factors of 26: 1, 2, 13, 26.
Factors of 40: 1, 2, 4, 5, 8, 10, 20, 40.
Common factors: 1 and 2. The greatest of these is 2.

Method 2: prime factorization

26 = 2 × 13
40 = 2 × 2 × 2 × 5

GCF: multiply the prime factors both numbers share: 2 = 2.

LCM: multiply every prime the maximum number of times it appears in either number: 2 × 2 × 2 × 5 × 13 = 520.

Method 3: Euclidean algorithm (GCF)

Divide the larger number by the smaller and repeat with the remainder until it is 0. The last non-zero remainder is the GCF.

40 = 1 × 26 + 14
26 = 1 × 14 + 12
14 = 1 × 12 + 2
12 = 6 × 2 + 0

The last non-zero remainder is 2, so GCF(26, 40) = 2.

LCM by listing multiples

Multiples of 26: 26, 52, 78, 104, 130, 156, 182, 208, 234, ...
Multiples of 40: 40, 80, 120, 160, 200, 240, 280, 320, 360, ...
The first number in both lists is 520.

Check: GCF × LCM = product

2 × 520 = 1,040 = 26 × 40. This always holds for two numbers, so you can find the LCM as (26 × 40) ÷ 2 = 520.

Simplifying the fraction 26/40

Divide the top and bottom by the GCF 2: 26/40 = 13/20.

GCF and LCM of similar pairs

Numbers	GCF	LCM
2 and 26	2	26
3 and 26	1	78
4 and 26	2	52
5 and 26	1	130
6 and 26	2	78
7 and 26	1	182
2 and 40	2	40
3 and 40	1	120
4 and 40	4	40
5 and 40	5	40
6 and 40	2	120
7 and 40	1	280

See also: factors of 26 · factors of 40.

Different numbers? Use the GCF and LCM calculator (any amount of numbers) or browse all GCF and LCM pairs.