Denominator[expr] gives the denominator of expr.
Divide
(Built-in Mathematica Symbol) x/y or Divide[x, y] is equivalent to x y^-1.
Divisors[n] gives a list of the integers that divide n.
EulerGamma is Euler's constant \[Gamma], with numerical value \[TildeEqual] 0.577216.
EvaluationMonitor is an option for various numerical computation and plotting functions that gives an expression to evaluate whenever functions derived from the input are ...
FiniteAbelianGroupCount[n] gives the number of finite Abelian groups of order n.
GoldenRatio is the golden ratio \[Phi] = 1/2 (Sqrt[5] + 1), with numerical value \[TildeEqual] 1.61803.
IntegerExponent[n, b] gives the highest power of b that divides n.
InverseBetaRegularized[s, a, b] gives the inverse of the regularized incomplete beta function.
InverseGammaRegularized[a, s] gives the inverse of the regularized incomplete gamma function.