There certainly does not need to be an 'and'. This is one hundred eighty four. It could ALSO be one hundred 'and' eighty four, but it by no means NEEDS to be.
I've seen a lot of people writing Poles writing number into one word, for example, they would write "dziewięćdziesiątdziewięć" instead of "dziewięćdziesiąt dziewięć". Do they do this on purpose just to make long polish words?
Well, for normal numerals it's not okay. But you can encounter it with some adjectives for example. „Dziewięćdziesiątdziewięć” is not okay, but „dziewięćdziesięciodziewięciometrowy” is a valid word.