Is 21 a Prime Number? Why or Why Not Explained

Discover why 21 is not a prime number by exploring its divisors and understanding the definition of prime numbers.

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No, 21 is not a prime number. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 21 can be divided evenly by 1, 3, 7, and 21, making it a composite number, not a prime.

FAQs & Answers

  1. What makes a number prime? A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
  2. Why is 21 not a prime number? 21 is not prime because it can be evenly divided by 1, 3, 7, and 21, which means it has divisors other than 1 and itself.
  3. What are the divisors of 21? The divisors of 21 are 1, 3, 7, and 21.

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For more insights into prime numbers and divisibility rules, check out our videos on how to identify prime numbers and understand composite numbers in mathematics.

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