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!

Lesson Summary:

Is 1 a prime number?

No, it is not a prime number.

Is 1 a composite number?

No, it is not a composite number.

What are the factors of 1?

There is only one factor of 1 i.e. 1.

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.

Try it Yourself: Prime Numbers Calculator

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

Also Check: How to Find Prime Numbers

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.

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