21 milimeters equals 21,000,000 nanometers.
Convert 21 milimeters into meters, kilometers, decimeters, centimeters, micrometers, picometers, inches, feet, yards, miles, hands, lightyears, astronomical units, parsecs, etc...
Convert 21000000 nanometers into meters, kilometers, decimeters, centimeters, micrometers, picometers, inches, feet, yards, miles, hands, lightyears, astronomical units, parsecs, etc...