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Is 18 a Prime Number?

Is 18 a prime number? Numbers having only 2 factors, i.e. 1 and the number itself are known as prime numbers whereas numbers with more than 2 factors are known as composite. The answer to the question whether 18 is a prime or composite is - "18 is a composite number." Now, let us find out how and why is 18 a prime number or a composite number?

Is 18 a prime number? - No
Is 18 a composite number? - Yes
Is 18 a perfect square? - No
Prime Factors of 18 - 2, 3
Factors of 18 - 1, 2, 3, 6, 9, 18

Is 18 a Prime or Composite?

Is 18 a Prime Number?

No, 18 is not a prime number. The number 18 is divisible by 1, 2, 3, 6, 9, 18. For a number to be classified as a prime number, it should have exactly two factors. Since 18 has more than two factors, i.e. 1, 2, 3, 6, 9, 18, it is not a prime number.

Is 18 a Prime Number?

Why is 18 not a Prime Number?

To understand whether 18 is composite or prime, it is important to find its factors.

Factors of 18: 1, 2, 3, 6, 9, 18

Since 18 has more than 2 factors, we can say that 18 is not a prime number.

☛ Prime Number Calculator

Is 18 a Composite Number?

Yes, since 18 has more than two factors i.e. 1, 2, 3, 6, 9, 18. In other words, 18 is a composite number because 18 has more than 2 factors.

Problem Statements:

Is 18 a Prime Number?	No
Is 18 a Composite Number?	Yes
Is 18 an Odd Number?	No
Square Root of 18	4.242641
Cube Root of 18	2.620739
Is 18 a Perfect Cube?	No
Is 18 an Even Number?	Yes
Is 18 a Perfect Square?	No
Multiples of 18	18, 36, 54, 72, 90, 108, 126, 144, 162, 180
Square of 18	324

Fun Facts:

Prime numbers greater than 5 can be represented in the form of either 6n + 1 or 6n - 1. Example - 71 is a prime number and it can be written as 71 = 6 × 12 - 1
1 is neither prime nor composite.
Euler discovered a polynomial n² + n + 41 that produces prime numbers for values of n that lie between 0 and 39 inclusive. It can generate 40 prime numbers for 0 <= n <= 39.

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