Yes, TOTALITARIAN is a Scrabble word!

Letter values in Scrabble US: T 1, O 1, T 1, A 1, L 1, I 1, T 1, A 1, R 1, I 1, A 1, N 1.

Is it a valid word?

TOTALITARIAN is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

characterized by a government in which the political authority exercises absolute and centralized control
of or relating to the principles of totalitarianism according to which the state regulates every realm of life