How many total protons neutrons and electrons are in an atom of iodine with a mass number of 127

The atomic number of iodine (53) tells us that a neutral iodine atom contains 53 protons in its nucleus and 53 electrons outside its nucleus. Because the sum of the numbers of protons and neutrons equals the mass number, 127, the number of neutrons is 74 (127 - 53 = 74) ... i think ...