A megabyte is officially 1 000 000 bytes, because mega means 1 000 000.

To resolve the confusion with 1 048 576 in data processing, in December 1998 the International Electrotechnical Commission created new prefixes for binary multiples (q.v. for fuller explanation).

In brief: kibi is 1024 (= 2¹⁰), mebi is 1 048 576 (= 1024² = 2²⁰), then gibi, tebi, pebi, ebi. Their symbols have a capital letter then i: thus KiB = kibibyte, MiB, GiB etc.

The megabyte usually used to mean mebibyte in computing, but the new more accurate binary prefixes should now be used.

Megabyte is the main bad guy in the TV show Reboot. A big, bluish-purple, metal-skinned, tyrannical computer virus with detachable legs, retractable claws, the voice talents of Tony Jay, and serious attitude. His forces include his bungling henchmen, Hack and Slash, a team of slightly goofy black ops agents, and a smallish army.
Megabyte's main goals seem to be taking over the Supercomputer, or failing that, the system of Mainframe. He is the arch rival of Guardian 452, Bob. His sister, Hexadecimal, also has a habit of getting in his non-existant hair.