This information comes straight from Junichi's Twitter...
N's real name is Natural Harmonia Gropius, with "N" coming from the term natural number.
With his high IQ, N exceeds humans.
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.
According to Masuda, rumors have it that N 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.