**Public Function Factorial( _
ByVal vX As Variant _
) As Variant**

**Return the factorial of the number X. **

The factorial of X is the product of every number between 1 and X, except that the factorial of 1 (one) is 1.

**Examples:** IsNull(Factorial(-1)) = True
Factorial(0) = 1
Factorial(1) = 1
Factorial(2) = 2
Factorial(3) = 6
Factorial(4) = 24
Factorial(5) = 120
Factorial(67) = 3.64711109181887E+94
Factorial(170) = 7.257415615308E+306
IsNull(Factorial(171)) = True

**See also:** Combinations Function
CombinationsWithRepetitions Function
Permutations Function
FACT Function (Microsoft Excel)

**vX:** The number whose factorial will be returned as a Double (precision floating-point) numeric value. Function returns Null if vX is Null, cannot be interpreted as a number, or is not between 0 (zero) and 170 (the result would be greater than MaxDouble). vX is rounded down to the nearest integer.

**Note:** This function will not generate the factorial of a floating point number; it will ignore the fractional part of any floating point numbers by applying the Visual Basic Fix function to the number.

**v1.5 Pro Note:** The argument names and the implementation of this function has changed. Copyright 1996-1999 Entisoft

Entisoft Tools is a trademark of Entisoft.