Is 40 a prime number?

No, 40 is not a prime number. It is a composite number: it is even, so it is divisible by 2.

Why 40 is not prime

40 has divisors other than 1 and itself. The smallest is 2: 40 ÷ 2 = 20.

Prime factorization: 40 = 2 × 2 × 2 × 5 = 2³ × 5.

Quick facts about 40

Even or odd: even.
Nearest primes: 37 below and 41 above.
Primes up to 40: 12.

Is it prime? Nearby numbers

Number	Prime?
36	No, 2 × 2 × 3 × 3
37	Yes
38	No, 2 × 19
39	No, 3 × 13
41	Yes
42	No, 2 × 3 × 7
43	Yes
44	No, 2 × 2 × 11

More about 40: factors of 40 · 40 squared · square root of 40 · 40 in binary · 40 in Roman numerals.

Another number? Use the prime number checker for any value, or see the list of prime numbers.