$VersionNumber (Built-in Mathematica Symbol)

$VersionNumber is a real number which gives the current Mathematica kernel version number, and increases in successive versions.

Integer and Number Theoretic Functions (Mathematica Tutorial)

Some integer functions. The remainder on dividing 17 by 3. The integer part of 17/3.

NumberQ (Built-in Mathematica Symbol)

NumberQ[expr] gives True if expr is a number, and False otherwise.

New in 6.0: Number Theory & Integer ... (Mathematica Guide)

NumberPoint (Built-in Mathematica Symbol)

NumberPoint is an option for NumberForm and related functions which gives the string to use as a decimal point.

NumberSigns (Built-in Mathematica Symbol)

NumberSigns is an option for NumberForm and related functions which gives strings to use as signs for negative and positive numbers.

NumberString (Built-in Mathematica Symbol)

NumberString represents the characters of a number in StringExpression.

NumberSeparator (Built-in Mathematica Symbol)

NumberSeparator is an option for NumberForm and related functions which gives the string to insert at breaks between digits.

NumberMarks (Built-in Mathematica Symbol)

NumberMarks is an option for InputForm and related functions that specifies whether ` marks should be included in the printed forms of approximate numbers.

Primes (Built-in Mathematica Symbol)

Primes represents the domain of prime numbers, as in x \[Element] Primes.