228 (two hundred
ndtwenty-eight) is the
natural number
In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...
following
227 and preceding
229.
In mathematics
228 is a
refactorable number
and a
practical number.
There are 228
matchings in a
ladder graph with five rungs.
228 is the smallest even number ''n'' such that the numerator of the ''n''th
Bernoulli number
In mathematics, the Bernoulli numbers are a sequence of rational numbers which occur frequently in analysis. The Bernoulli numbers appear in (and can be defined by) the Taylor series expansions of the tangent and hyperbolic tangent function ...
is divisible by a nontrivial
square number
In mathematics, a square number or perfect square is an integer that is the square (algebra), square of an integer; in other words, it is the multiplication, product of some integer with itself. For example, 9 is a square number, since it equals ...
that is
relatively prime
In number theory, two integers and are coprime, relatively prime or mutually prime if the only positive integer that is a divisor of both of them is 1. Consequently, any prime number that divides does not divide , and vice versa. This is equiv ...
to ''n''.
The binary form of 228 contains all the two digit binary numbers in sequence from highest to lowest (11 10 01 00).
References
Integers
{{Num-stub