2 syllables
Both words? Being syllable addends? 5 total, for both words
syl-la-ble
4 syllables am- phi- bi- an
It can be pronounced two ways. 1) ADvertise is the way I pronounce it. 2) I've never heard it pronounced adVERtise. 3) Though some people do put a bit of emphasis on the last syllable with adverTISE...