Find Prime Number In C++

What is a PRIME NUMBER?
” A Natural number greater than 1 which has only two divisor 1 and itself is called prime number “.
For Example:
5 is prime, because it has only two divisors 1 and itself.

C++ Program

#include<iostream.h>
#include<conio.h>
        void main() {
	//clrscr();
	int number,count=0;
	cout<<"ENTER NUMBER TO CHECK IT IS PRIME OR NOT ";
	cin>>number;
	for (int a=1;a<=number;a++) {
		if(number%a==0) {
			count++;
		}
	}
	if(count==2) {
		cout<<" PRIME NUMBER \n";
	} else {
		cout<<" NOT A PRIME NUMBER \n";
	}
	//getch();
}