Pi (π) is an irrational number. This means that it cannot be expressed as a fraction of two integers. In simpler terms, there are no whole numbers a and b (where b is not zero) such that π = a/b.
In fact, π is a transcendental number, which is a step further than being just irrational. This means that it is not only non-repeating and non-terminating as a decimal, but it cannot be the root of any non-zero polynomial equation with rational coefficients.
The decimal representation of π starts with 3.14159 and goes on infinitely without repeating. Because of this unique property, π has fascinated mathematicians for centuries and is vital in various fields, including geometry, trigonometry, and calculus.