A number that is not prime is called a composite number. Composite numbers can be divided up into smaller whole numbers called factors. A prime number has no factors other than one and itself.
Know MoreMost integers, or counting numbers, are composite numbers. Primes are comparatively rare. All even numbers are divisible by two, so they are composite numbers. As a number grows in magnitude, the chance that it is divisible by some lesser number increases, so primes become fewer and fewer as magnitude increases. By convention, one is not considered prime. The number two is considered prime because even though it is an even number, it is only divisible by one and itself.
Learn more about NumbersThe number 21 is not a prime number. Prime numbers are numbers greater than one that are evenly divisible by only 1 and themselves. As the number 21 has multiple factors, including 1, 21, 3 and 7, it does not meet the definition of a prime number.
Full Answer >The number 33 is not a prime number. Prime numbers only have factors of themselves and 1. The positive factors of 33 are 1, 3, 11 and 33.
Full Answer >The number 67 is a prime number by definition. A prime number is any positive number that can only be divided evenly by the number one and itself. It must also be a whole number greater than one, no fractions or decimals.
Full Answer >Sixty-three is not a prime number. Sixty-three is classified as a composite number because it has divisors, and can be composed of other numbers than number one.
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