Yes, TOTIPOTENCY is a Scrabble word!

Letter values in Scrabble US: T 1, O 1, T 1, I 1, P 3, O 1, T 1, E 1, N 1, C 3, Y 4.

Is it a valid word?

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

the ability of a cell to give rise to unlike cells and so to develop a new organism or part

Not playable in Scrabble US: TOTIPOTENCE.