composite number

plural composite numbers

1. mathematicsA (nonzero) natural number that is expressible as the product of two (or more) natural numbers other than itself and 1.

   It is evident, moreover, that if a composite number terminates in any one of the digits 1, 3, 7, 9, no one of its factors can be the number 5, or any number ending in 5.

   1853, Edward Hinkley, Tables of the Prime Numbers and Prime Factors of the Composite Numbers from 1 to 100,000, page 13

   2 more examples

   The above remark applies also to many composite numbers which are not Carmichael numbers, but which are still not shown to be composite by Fermat's theorem for a specific base a.[…]Therefore, using Euler's criterion or a strong primality test with enough bases will finally reveal any composite number or, alternatively, prove the primality of any prime N.

   1994, Hans Riesel, Prime Numbers and Computer Methods for Factorization, 2nd edition, Springer (Birkhäuser), →ISBN, page 91

   It is interesting that in each interval composite numbers are one-to-one assigned to the comparable composite knots while prime numbers are one-to-one assigned to prime knots.

   2006, Sze Kui Ng, Quantum Invariant of 3-Manifolds, Samuel F. Neilson (editor), New Research on Three-manifolds and Mathematics, Nova Science Publishers, page 47

   Antonyms: prime number