sep·ten·de·cil·lion 
(sĕp′tĕn-dĭ-sĭlyən)
(sĕp′tĕn-dĭ-sĭlyən)n.
1. The cardinal number equal to 1054.
2. Chiefly British The cardinal number equal to 10102.
[Latin septendecim, seventeen (septem, seven; see sept in the Appendix of Indo-European roots + decem, ten; see DECI-) + (M)ILLION.]
sep′ten·de·cillion adj.
sep′ten·de·cillionth adj., adv. & n.