twenty-two vs .22

twenty-two and .22 both are nouns.

Word	Noun	Adjective	Verb	Adverb
twenty-two	Yes	Yes	No	No
.22	Yes	No	No	No

As nouns, twenty-two and .22 are synonyms defined as:

twenty-two (noun)	.22 (noun)
a .22 caliber firearm (pistol or rifle)	a .22 caliber firearm (pistol or rifle)
the cardinal number that is the sum of twenty-one and one

twenty-two (adjective)	.22 (adjective)
being two more than twenty