A megahertz is one million (or 106) hertz.
See hertz, kilohertz (one thousand hertz), gigahertz[?] (109 hertz), terahertz[?] (1012 hertz), and petahertz[?] (1015 hertz).
... households out of which 43.7% have children under the age of 18 living with them, 70.4% are married couples living together, 9.9% have a female householder with no husband ...