An even power of a quantity 
is a power 
whose exponent 
is an even integer. For a polynomial or power series,
the even powers are therefore 1, 
, 
,
, ....
The even part of a polynomial is the sum of its monomials containing even powers of the variable. An even function analytic at the origin has a Maclaurin series containing only even powers.
In number theory, an even power is also a number of the form 
, where 
is a positive integer
and 
is an even
integer. The distinct even powers are precisely the square
numbers. Every even power greater than 1 in this sense is a perfect
power.
