Is 561 a Prime Number?

Is 561 a prime number? "No, 561 is not a prime number." A number can be classified as prime or composite depending on the factors it contains; it could either have only 2 factors or more than 2 factors. Numbers like 31 with only 2 factors, i.e. 1 and 31 are called prime numbers. However, numbers like 462 with more than 2 factors are called composite numbers. Let us find out how and why is 561 a prime number or a composite number?

• Is 561 a prime number? - No
• Is 561 a composite number? - Yes
• Is 561 a perfect square? - No
• Factors of 561 - 1, 3, 11, 17, 33, 51, 187, 561
• Prime Factors of 561 - 3, 11, 17

Is 561 a Prime Number?

No, 561 is not a prime number. The number 561 is divisible by 1, 3, 11, 17, 33, 51, 187, 561. For a number to be classified as a prime number, it should have exactly two factors. Since 561 has more than two factors, i.e. 1, 3, 11, 17, 33, 51, 187, 561, it is not a prime number.

Why is 561 not a Prime Number?

To understand whether 561 is prime or composite, it is important to find its factors.

Factors of 561: 1, 3, 11, 17, 33, 51, 187, 561

Since 561 has more than 2 factors, we can say that 561 is not a prime number.

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Is 561 a Composite Number?

Yes, since 561 has more than two factors i.e. 1, 3, 11, 17, 33, 51, 187, 561. In other words, 561 is a composite number because 561 has more than 2 factors.

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Fun Facts:

• 23 is the smallest prime number having consecutive digits.
• 5 is the only prime number having the last digit as 5.
• A palindrome prime is a prime number that when read in reverse order results in the same number. Examples - 10601, 11311, 12421

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