The FACTORIAL function returns an integer that is the factorial of argument-1. The type of this function is integer. 
 
  General Format
 
	  
	  
 
  Arguments
 
	   
	 - Argument-1 must be an integer greater than or equal to zero. 
	 
Returned Values
 
	   
	 - If the value of argument-1 is zero, the value 1 is returned. 
	 
- If the value of argument-1 is positive, its factorial is returned. 
	 
- Floating-point format is used for numeric non-integer results.