public static boolean isPrime(long i) {
        if (i < 2)
            return false;
        if (i == 2 | i == 3) {
            return true;
        }
        if (i % 2 == 0 || i % 3 == 0)
            return false;

        String asS = String.valueOf(i);
        if (asS.endsWith("5") | asS.endsWith("0"))
            return false;

        long sqrtN = (long) Math.sqrt(i) + 1;
        for (long j = 6L; j <= sqrtN; j += 2) {
            if (i % (j - 1) == 0 || i % (j + 1) == 0)
                return false;
        }

        return true;
    }