PIN vs PIN number

PIN and PIN number both are nouns.

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

As nouns, PIN and PIN number are synonyms defined as:

PIN and PIN number: a number you choose and use to gain access to various accounts

Other synonyms of PIN include personal identification number.

PIN (noun)	PIN number (noun)
a number you choose and use to gain access to various accounts	a number you choose and use to gain access to various accounts