septendecillion
noun
sep·ten·de·cil·lion (ˌ)sep-ˌten-di-ˈsil-yən 
often attributive
US : a number equal to 1 followed by 54 zeros see Table of Numbers
also, British : a number equal to 1 followed by 102 zeros see Table of Numbers
Word History
Etymology
Latin septendecim seventeen (from septem seven + decem ten) + English -illion (as in million) — more at ten
First Known Use
1898, in the meaning defined above