def is_prime_number(n):
    """
      Deterine if a positive integer is prime or not.
    """
    if n in (2, 3):
        return True
    if 2 > n or 0 == n % 2:
        return False
    if 9 > n:
        return True
    if 0 == n % 3:
        return False
 
    return not any(map(
        lambda x: 0 == n % x or 0 == n % (2 + x),
        range(5, 1 + int(n ** 0.5), 6)
    ))