29th vs twenty-ninth

29th and twenty-ninth both are adjectives.

Word	Noun	Adjective	Verb	Adverb
29th	No	Yes	No	No
twenty-ninth	No	Yes	No	No

As adjectives, 29th and twenty-ninth are synonyms defined as:

29th (adjective)	twenty-ninth (adjective)
coming next after the twenty-eighth in position	coming next after the twenty-eighth in position