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Built-in Mathematica Symbol

ExactNumberQ

ExactNumberQ[expr]
returns True if expr is an exact real or complex number, and returns False otherwise.

ExactNumberQ[expr] gives True if expr has head Integer or Rational, or is a complex number whose components both have heads Integer or Rational.

ExactNumberQ tests whether an object is explicitly an exact number:

Both real and imaginary parts of a complex number must be exact:

ExactNumberQ is false for symbolic objects that represent numbers:

You can test these with NumericQ:

Numbers are considered either exact or approximate (inexact):

Exact numbers have Precision

Exact numbers have Head Integer, Rational, or Complex:

A function equivalent to ExactNumberQ: