USA vs Social Security number

USA and Social Security number both are nouns.

Word	Noun	Adjective	Verb	Adverb
USA	Yes	No	No	No
Social Security number	Yes	No	No	No

USA (noun)	Social Security number (noun)
the army of the United States of America; the agency that organizes and trains soldiers for land warfare	the number of a particular individual's Social Security account
North American republic containing 50 states - 48 conterminous states in North America plus Alaska in northwest North America and the Hawaiian Islands in the Pacific Ocean; achieved independence in 1776