+33653 pi is the ratio of the circumference to the diameter of a circle.
It is an irrational number, which means it cannot be expressed exactly as a ratio of two whole numbers (though 22/7 and 355/113 are approximations that are often used). It also cannot be expressed exactly as a decimal because its decimal expansion is infinitely long (though 3.14 and the value given by Guest #1 are approximations).
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