3.9735067984839e+21 milimeters equals 420 lightyears.
Convert 3.9735067984839e+21 milimeters into meters, kilometers, decimeters, centimeters, micrometers, nanometers, picometers, inches, feet, yards, miles, hands, astronomical units, parsecs, etc...
Convert 420 lightyears into meters, kilometers, decimeters, centimeters, micrometers, nanometers, picometers, inches, feet, yards, miles, hands, astronomical units, parsecs, etc...