composite number
A composite number^{} is a positive integer which is not prime and not equal to 1. That is, $n$ is composite if $n=ab$, with $a$ and $b$ natural numbers both not equal to 1.
Examples.

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1 is not composite (and also not prime), by definition.

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2 is not composite, as it is prime.

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15 is composite, since $15=3\cdot 5$.

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93555 is composite, since $93555={3}^{5}\cdot 5\cdot 7\cdot 11$.

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52223 is not composite, since it is prime.
More generally, we can define compositeness any time there is an ambient notion of an irreducible element^{}. In an integral domain^{}, for example, an element is said to be composite if it neither zero, a unit, nor irreducible.
Title  composite number 

Canonical name  CompositeNumber 
Date of creation  20130322 12:39:37 
Last modified on  20130322 12:39:37 
Owner  mathcam (2727) 
Last modified by  mathcam (2727) 
Numerical id  9 
Author  mathcam (2727) 
Entry type  Definition 
Classification  msc 11A41 
Synonym  composite 