C code for finding factorial of a given number

#include<stdio.h>
#include<conio.h>
void main()
{
long long int i,factorial,n;
clrscr();
printf("enter number:");
scanf("%llu",&n);
factorial=1;
for(i=1;i<=n;i++) {
factorial=factorial*i;}
printf("input number's factorial=%llu",factorial);
getch();
}