Editing Divisor (section)

== General ==
Divisors can be [[negative number|negative]] as well as positive, although often the term is restricted to positive divisors. For example, there are six divisors of 4; they are 1, 2, 4, −1, −2, and −4, but only the positive ones (1, 2, and 4) would usually be mentioned.

1 and −1 divide (are divisors of) every integer. Every integer (and its negation) is a divisor of itself. Integers divisible by 2 are called [[even and odd numbers|even]], and integers not divisible by 2 are called [[even and odd numbers|odd]].

1, −1, <math>n</math> and <math>-n</math> are known as the '''trivial divisors''' of <math>n.</math> A divisor of <math>n</math> that is not a trivial divisor is known as a '''non-trivial divisor''' (or strict divisor{{refn|{{cite web| url = https://perso.crans.org/cauderlier/org/ITP17_draft.pdf| title = FoCaLiZe and Dedukti to the Rescue for Proof Interoperability by Raphael Cauderlier and Catherine Dubois}}}}). A nonzero integer with at least one non-trivial divisor is known as a [[composite number]], while the [[Unit (ring theory)|units]] −1 and 1 and [[prime number]]s have no non-trivial divisors.

There are [[divisibility rule]]s that allow one to recognize certain divisors of a number from the number's digits.