one hundred twenty-five vs 125

one hundred twenty-five and 125 both are adjectives.

Word	Noun	Adjective	Verb	Adverb
one hundred twenty-five	No	Yes	No	No
125	No	Yes	No	No

As adjectives, one hundred twenty-five and 125 are synonyms defined as:

one hundred twenty-five and 125: being five more than one hundred twenty

Other synonyms of one hundred twenty-five include cxxv.

one hundred twenty-five (adjective)	125 (adjective)
being five more than one hundred twenty	being five more than one hundred twenty