Is 2100 nisen hyaku or nisen yihyaku ? Similarly for 2210, nisen nihyaku juu or nisen nihyaku yijuu ?
Where are you getting this "yi" sound from? To answer your question, larger numbers that start with 1 do not require that the "one" be spoken. Similar to "a hundred" and "a thousand" in English, it can be and usually is omitted. So 1100 would "sen hyaku" (though you could say issen hyaku... but I would not say issen ippyaku, that just sounds weird...) And there would never be a "one" in front of "ten" either, so your example 2210 would be "ni sen ni hyaku juu"