cardinal number vs cardinal numeral

cardinal number and cardinal numeral both are nouns.

Word	Noun	Adjective	Verb	Adverb
cardinal number	Yes	No	No	No
cardinal numeral	Yes	No	No	No

As nouns, cardinal number and cardinal numeral are synonyms defined as:

cardinal number and cardinal numeral: (grammar) A word that expresses a countable quantity.

cardinal number (noun)	cardinal numeral (noun)
(grammar) A word that expresses a countable quantity.	(grammar) A word that expresses a countable quantity.
the number of elements in a mathematical set; denotes a quantity but not the order