Impartable is made from the verb impart, which means “to share information, to communicate,” as in “I imparted my plans to my friend.” So, impartable naturally means “able to be communicated”:
Spiritual experiences are not easily impartable; they transcend words.
Be aware that some dictionaries do not list impartable, because it is a form that an English speaker might simply make-up from impart, the same way we might call a movie “watch-able” or a path “walk-able.”
Impartible is a proper word, meaning “not able to be divided into parts” (not-part-able):
Physicists still do not know whether the smallest particles of matter are impartible or not.
You can remember the difference between these words by keeping in mind how they are broken apart:
impartable = impart + able
impartible = im + part + ible .(prefix im- meaning not in this case)