Is 1 a Prime Number?

Number 1 has positive divisors as 1 and itself. According to the definition of prime numbers, any number having only two positive divisors are known as prime numbers. So, is 1 a prime number or not? Is it a composite number?

The answer to this question is: No, 1 is not a prime number and it is not a composite number!

Why is 1 not a Prime Number?

The answer to this lies in the definition of prime numbers itself. For a number to be called as a prime number, it must have only two positive factors. Now, for 1, the number of positive divisors or factors is only one i.e. 1 itself. So, number one is not a prime number.

Note: 2 is the smallest number that satisfies the definition of prime numbers.

So, What is 1 Called if it is Not a Prime Number?

The number one is neither a prime nor a composite. In mathematics, there are various categories of numbers in which number 1 falls. So, 1 can be called by any of the following:

• A natural number
• An odd number
• A rational number
• A positive integer
• A whole number

But, Why is 1 Not a Composite Number?

The answer to this also lies in the definition of composite numbers. According to the definition, a composite number is a natural number which more than two positive factors. But, 1 has only 1 factor i.e. 1 itself. So, one is not a composite number.