number one vs number 1

number one and number 1 both are nouns.

Word	Noun	Adjective	Verb	Adverb
number one	Yes	No	No	No
number 1	Yes	No	No	No

As nouns, number one and number 1 are synonyms defined as:

Other synonyms of number one include first.

number one (noun)	number 1 (noun)
a reference to yourself or myself etc.; `take care of number one' means to put your own interests first	the first element in a countable series
the first element in a countable series
the first or highest in an ordering or series