Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
sescentĭes (less correctly sexc-), num. adv. [sescenti], six hundred times: sescenties HS., six hundred times a hundred thousand, sixty millions of sesterces, Cic. Att. 4, 16 C, 14; so, sestertium sescenties, Plin. Ep. 2, 20, 13: sescenties vicies, Lampr. Commod. 15 (in Plaut. Men. 5, 4, 8, the true read. is sescentos).