octodecillion
noun
oc·to·de·cil·lion ˌäk-tō-di-ˈsil-yən 
US : a number equal to 1 followed by 57 zeros see Table of Numbers
also, British : a number equal to 1 followed by 108 zeros see Table of Numbers
Word History
Etymology
Latin octodecim eighteen + English -illion (as in million)
First Known Use
1848, in the meaning defined above