periodical vs number

periodical and number both are nouns.

Word	Noun	Adjective	Verb	Adverb
periodical	Yes	Yes	No	No
number	Yes	No	Yes	No

As nouns, number is a hyponym of periodical; that is, number is a word with a more specific, narrower meaning than periodical:

Other hyponyms of periodical include digest, pictorial, serial, serial publication, series, organ, issue, journal, review.

periodical (noun)	number (noun)
a publication that appears at fixed intervals	an item of clothing
	the property possessed by a sum or total or indefinite quantity of units or individuals
	a clothing measurement
	one of a series published periodically
	a symbol used to represent a number
	a numeral or string of numerals that is used for identification and may be attached to accounts, memberships, etc.
	the number is used in calling a particular telephone
	a short performance that is part of a longer program
	the grammatical category for the forms of nouns and pronouns and verbs that are used depending on the number of entities involved (singular or dual or plural)
	a numbered item in a series
	a select company of people
	a concept of quantity involving zero and units

periodical (adjective)	number (adjective)
happening or recurring at regular intervals

periodical (verb)	number (verb)
	place a limit on the number of
	determine the number or amount of
	enumerate
	give numbers to
	add up in number or quantity
	put into a group