A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... of it may be restricted by the copyright holder. The context is most commonly digital (ie, as in a computer or computerized device), hence the 'digital' in DRM. I ...