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 NumbersNine is not a prime number. It is a composite number, because it has more than two factors. A prime number is only divisible by one and by itself, and nine is divisible by one and by nine, but it is also divisible by the number three.
Full Answer >The number 49 is divisible by seven, so it is not a prime number. A prime number is a number that is only divisible by the number 1 and itself.
Full Answer >The number 69 is not a prime number, as it has the factors of 3 and 23. A prime number is one which is only evenly divisible by itself and the number 1.
Full Answer >The 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.
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