Fac

fac returns the factorial of an integer value.

Syntax

   fac(INTEGER_EXPR)

INTEGER_EXPR is an expression returning an integer value. 0 <= INTEGER_EXPR <= 58

   VALUE=fac(6) : # returns 720
   SIXTEEN = fac(16) / fac(15)
   ARRANGEMENT = fac(N) / (fac(P) * fac(N-P))

fac(N) returns N(N-1)(N-2)* ... 21

By convention, fac(0) equals 1.

The type of result is Integer or Decimal depending on whether the result is greater or smaller than 2^31-1.

Error code	Description
10	The argument is not numeric.
13	Calculation overflow (x is too big, greater than 58).
58	The argument is not an integer.