is 1 a prime number?

Question

please let me know

christoph · Answer

1 is not a prime number !

 https://mathworld.wolfram.com/PrimeNumber.html

Vijo · Answer

No, 1 is not a prime number.

2 is the smallest and the only even prime number.

rxs0005 · Answer

the only even prime num = 2

rest all odd startign from 3 

1 not a prime

HongHu · Answer

1 is not a prime number. But if asked how many divisors a number has, 1 would be counted. Am I correct?

banerjeea_98 · Answer

Ya, 1 is a factor of all, but not prime.

nocilis · Answer

Also, all prime numbers other than 2 and 3 can be represented as 6n-1 or 6n+1 (n>=1).

But bewarned, not all numbers that can be represented as 6n-1 or 6n+1 are primes, such as number 91 (13X7) which is not prime.

MA · Answer

prime is divided by itself and 1. prime must have 2 dividers, one, itself and another, 1. on the ground that it (1) has not two dividers, it is not considered as prime.

HongHu · Answer

Wow. How do you know that? Is there a prove somewhere?

Let me see ... Ok, all numbers can be written as 6n, 6n+1, 6n+2, 6n+3, 6n+4, 6n+5. And obviously 6n, 6n+2, 6n+3, 6n+4 are not prime numbers. So the only thing that is left would be 6n+1 and 6n+5 (or 6n-1).

That's pretty cool.

By the same token, all prime numbers can be written as 4n-1 and 4n+1 too. Though it may not be that much helpful.

anirban16 · Answer

2 is the smallest prime number.

Good logic for 6n and 4n stuff.

is 1 a prime number?

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