444444 + 5 is prime. Note that 444 is the only known number m such that mm + 5 is prime.
444 = (41 + 41+ 41) + (42 + 42 + 42) + (43 + 43 + 43) + (43 + 43 + 43).
In base 6, 444 is 2020.
St. Patrick founded the Irish city of Armagh in the year 444.
Source: Prime Curios!