from the Department of Usernames That Will Never Be Already Taken

[arethinn]

One of the most peculiar numeral words in English is "zenzizenzizenzic", which means "the eighth power of a number", as in "The zenzizenzizenzic of 2 is 256". It was used only once in English, in Robert Recorde's The Whetstone of Wit (1557). It is derived from an equally-obsolete "zenzic", which referred to the square of a number. It is the only English word with six Zs, and is thus, if I may be allowed to coin a term, hexazetic.

(http://phrontistery.info/numbers.html)

Then again, zenzic, but "zenzizenzizenzic" is 16 letters long and thus can't be a LJ user name. Aww.