# Definition:Even Integer/Definition 1

## Contents

## Definition

An integer $n \in \Z$ is **even** if and only if it is divisible by $2$.

## Also see

## Historical Note

The concept of classifying numbers as **odd** or **even** appears to have originated with the Pythagoreans.

It was their belief that **even numbers** are **female**, and **odd numbers** are **male**.

A commentator on Plato used the term **isosceles number** for an **even number**, in correspondence with the concept of an isosceles triangle. In a similar way an odd number was described as **scalene**.

## Sources

- 1965: Seth Warner:
*Modern Algebra*... (previous) ... (next): $\S 24$ - 1986: David Wells:
*Curious and Interesting Numbers*... (previous) ... (next): $2$ - 1997: David Wells:
*Curious and Interesting Numbers*(2nd ed.) ... (previous) ... (next): $2$