A genius, N excels in math enough to be called a math wizard.
N is quick-witted and has extreme mood swings.
N can see the past and future of people.
N believes he was born from Pokémon; the parents are unknown.
N loves Pokémon but keeps his distance from humans.
N believes he’s perfect.
Always putting Pokémon first is N's ideology.
Given how he is, he has been shunned by humans. In effect, he has a very strong connection with Pokémon.
In addition to the listed information, Junichi Masuda also talks about N's two themes in Black and White in relation to numbers, with his name's origin in mind.