one-hitter vs 1-hitter

one-hitter and 1-hitter both are nouns.

Word	Noun	Adjective	Verb	Adverb
one-hitter	Yes	No	No	No
1-hitter	Yes	No	No	No

As nouns, one-hitter and 1-hitter are synonyms defined as:

one-hitter and 1-hitter: a game in which a pitcher allows the opposing team only one hit

one-hitter (noun)	1-hitter (noun)
a game in which a pitcher allows the opposing team only one hit	a game in which a pitcher allows the opposing team only one hit