def is_prime(number):
    if number < 2:
        return False
    elif number == 2:
        return True
    elif not number & 1:
        return False

    for n in range(3, int(number**0.5)+1, 2):
        if number % n == 0:
            return False

    return True

print(1, "is prime", is_prime(1))
print(2, "is prime", is_prime(2))
print(4, "is prime", is_prime(4))
print(13, "is prime", is_prime(13))
print(55, "is prime", is_prime(55))
