what are numbers called that are not prime numbers?

Answer 1

composite numbers.

assuming you mean numbers that have more than one divisor other than 1. (1 and 0 are not composite, they're special cases.)

http://en.wikipedia.org/wiki/Composite_numbers

Answer 2

It depends on which set of "numbers" you are thinking of.

Among the whole numbers greater than 1, those which are not prime numbers are correctly and completely called "composite numbers".

The numbers 1 and 0 are neither prime nor composite. 1 is called a "unit".

Negative whole numbers are neither prime nor composite.

A "non-prime integer" would be any whole number except for the primes. However, if such a description came up in mathematics, it would probably exclude -1, 0 and 1, and there would be some extra words with it to say so.

Answer 3

Although it has been answered by the above people, I like to do this differently especially to others who may not know the real meaning ;-)

First, prime number is a +ve whole number greater than one which is divisible only by itself and one. An example is 7. See - it can only divide by 7 itself or 1. But another number, "6" for example, is not a prime number becos it can be divided by 2 and 3 (beside by 6 and 1), therefore it is not a prime number but mathematician called it a "composite" number as it is divisible by other smaller numbers other than 1 and by itself.
Cheers!

Answer 4

No need to get all technical...algebraically defined?

Prime numbers are numbers that cannot be divided evenly except by 1 and itself.

COMPOSITE numbers are not prime, but are made up of multiples of primes. For instance, 30 is a composite number, and can be written as:

2*3*5 (all primes)

0 or 1 are not considered as prime, nor composite.

Answer 5

Any non-prime natural number greater than 1 is called a composite number.

Natural numbers are the numbers which we normally use for counting, 1,2,3,4,5,6,7,8,9,10 etc. Some people call these counting numbers. Some people say that 0 is a natural number too.

Another name for these numbers is positive numbers. These numbers are sometimes written as +1 to show that they are different from the negative numbers. But not all positive numbers are natural (for example 1/2 is positive, but not natural).

Negative numbers are numbers less than zero.

Integers are all the positive numbers, all the negative numbers, and the number zero.

Rational numbers are numbers which can be written as fractions. This means that they can be written as a divided by b, where the numbers a and b are integers, and b is not equal to 0.

Irrational numbers are numbers which cannot be written as a fraction, but do not have imaginary parts.

The real numbers is a name for all the sets of numbers listed above

Imaginary numbers are formed by real numbers multiplied by the number i. This number is the square root of minus one (-1).

Complex numbers are numbers which have two parts; a real part and an imaginary part.

Answer 6

They are definitely called composite numbers. Someone above me wrote whole numbers. Every prime number is a whole number, so that answer is definitely not right. For example, 3 is a prime number, yet also a whole number. Composite numbers are numbers that have more than two factors. I made a program to spit out prime numbers, and something interesting is that 4, 124, 928, 991, 237, 973, 929 is a prime number. Sweet.

Answer 7

There's no name for them. Prime numbers are not an algebraically defined subgroup, although they are part of Z (integers), R (real numbers), Q(rational numbers), and many more.

Answer 8

positive integers which are not prime are either composite or neither prime nor composite(only 1 is of this type).

Answer 9

composite numbers.
composite numbers are positive integers that have more than two divisers.

Answer 10

whole numbers