interchangeability vs interchangeable

interchangeability is a noun but interchangeable is not a noun.

Word	Noun	Adjective	Verb	Adverb
interchangeability	Yes	No	No	No
interchangeable	No	Yes	No	No

interchangeability (noun)	interchangeable (noun)
the quality of being capable of exchange or interchange

interchangeability (adjective)	interchangeable (adjective)
	capable of replacing or changing places with something else; permitting mutual substitution without loss of function or suitability
	(mathematics, logic) such that the arguments or roles can be interchanged