How can I test for primality?

Question

I am writing a little library with some prime number related methods. As I\'ve done the groundwork (aka working methods) and now I\'m looking for some optimization. Ofcours

Answer 1

private static bool IsPrime(int number) {
    if (number <= 3)
        return true;
    if ((number & 1) == 0)
        return false;
    int x = (int)Math.Sqrt(number) + 1;
    for (int i = 3; i < x; i += 2) {
        if ((number % i) == 0)
            return false;
    }
    return true;
}

I can't get it any faster...