Prime Numbers
Numbers

# Is the prime number 21 is a prime number?

001 ###### 2012-03-29 09:54:11

21 is a composite number, not a prime, having prime factors 3x7.

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## Related Questions A prime number is any integer evenly divisible by only itself, and the number 1. Since 21 is divisible by 3 and 7, it is a composite number, not a prime number.No, 21 is not a prime number.21 is divisible by 1, 3, 7, & 21No. 21=3*7 There is an infinite number of prime numbers that are greater than 21. The next prime number after 21 is 23. 11 is a prime number but 21 is not a prime number as it is divisible by 3. 21 is the product of two prime numbers, three and seven. A prime number is defined as a number divisible only by one or itself. So ... NO ... 21 is not a prime number. 21 is composite number that is a multiple of 3. 31 is a prime number. No. The only factors of a prime number are 1 and itself. The only way that 21 could be a factor of a prime number is if it were a prime number, but it is not because 21 is also divisible by 3 and 7.  Who says it is? 21 is a composite number!  17 is a prime number, but 21 is not (21 = 3 * 7).   21 has two prime factors, 3 and 7.  21 is a Composite Number. A prime number is a whole number that only has two factors which are itself and one. A composite number has factors in addition to one and itself. 21 is divisible by 3 and 7. 21 isn't a prime number because it has more factors than just itself and 1 3x7=21 21x1=21 3 x 7 = 21, since both factors are prime, that is the prime factorization of 21. prime factor = prime number which can be divided into the given number with no remainder The prime factors of 21 are 3 and 7.      No 21 is not a prime number because it has more than two factors therefore it is a composite number 67 is a prime number, but 21 isn't. A prime number can only be evenly divided by '1' and itself. 21 can be evenly divided by 1, 3, 7, and 21.

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