This number is a prime.
The German beer Köstritzer dates back to 1543. [Luhn]
The year of publication of three landmarks in science: Andreas Vesalius published his De humani corporis fabrica libri septem (Basel: Johannes Oporinus), Nicolaus Copernic his De revolutionibus orbium celestium (Nuremberg: Johannes Petreius), and Robert Recorde his Arithmetic or the ground of Arts (London: Thomas Harper for John Harison). [Olry]