F# program to find Factorial of a Number

Program

open System
let rec factorial x =
    if x <= 1 then 1 
    else x * factorial(x-1)
Console.Write("Enter the number to get the factorial:\t")
let number = Int32.Parse(Console.ReadLine())
let result= factorial number
Console.WriteLine("Factorial of {0} is {1}\t", number, result)

Output

Enter the number to get the factorial:  8
Factorial of 8 is 40320