sep·til·lion 
(sĕp-tĭlyən)
(sĕp-tĭlyən)n.
1. The cardinal number equal to 1024.
2. Chiefly British The cardinal number equal to 1042.
[French : Latin septem, seven; see SEPTET + French -illion (as in million, million, from Old French milion; see MILLION).]
sep·tillion adj.