Yes, ECHIDNA is a Scrabble word!

Letter values in Scrabble US: E 1, C 3, H 4, I 1, D 2, N 1, A 1.

Is it a valid word?

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

a burrowing monotreme mammal covered with spines and having a long snout and claws for hunting ants and termites; native to New Guinea
a burrowing monotreme mammal covered with spines and having a long snout and claws for hunting ants and termites; native to Australia

Also: spiny anteater.