A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... painter Deaths: January 20 - Dmitri Ivanovich Mendeleev, Russian chemist and inventor of the Periodic table May 19 - Auguste Molinier, French historian July 14 - ...