XXVIII vs twenty-eight

XXVIII and twenty-eight both are nouns.

Word	Noun	Adjective	Verb	Adverb
XXVIII	Yes	No	No	No
twenty-eight	Yes	Yes	No	No

As nouns, XXVIII and twenty-eight are synonyms defined as:

XXVIII and twenty-eight: the cardinal number that is the sum of twenty-seven and one

Other synonyms of XXVIII include 28.

XXVIII (noun)	twenty-eight (noun)
the cardinal number that is the sum of twenty-seven and one	the cardinal number that is the sum of twenty-seven and one

XXVIII (adjective)	twenty-eight (adjective)
	being eight more than twenty