Short thread, but I discovered it since the release of the Galaxy Note_5.
In fact, The Samsung Galaxy Note 4 is called "Note4" without spaces within the Note word and the 4 number, just like the Note5. Just tap Settings, About Phone and look for the Device Name. If you're using an stock rom (or derivated from stock), you will notice that it says "Galaxy Note4". I think Samsung decided to change the name to close the gap with Galaxy S and A series (ie. Galaxy S6, A8 instead of S 6 or A 8).
Well, TL:DR: It's Note4 but we will write Note 4 forever. End of the Story :b
In fact, The Samsung Galaxy Note 4 is called "Note4" without spaces within the Note word and the 4 number, just like the Note5. Just tap Settings, About Phone and look for the Device Name. If you're using an stock rom (or derivated from stock), you will notice that it says "Galaxy Note4". I think Samsung decided to change the name to close the gap with Galaxy S and A series (ie. Galaxy S6, A8 instead of S 6 or A 8).
Well, TL:DR: It's Note4 but we will write Note 4 forever. End of the Story :b