If you make '1987' the subject of your sentence it would be a noun.
Noun
adverb
what part of speech is work
i want to know what part of speech is camping
what part of speech is beneath
what part of speech is eleven
A calendar year is a noun phrase.
Year is a noun.
in the year 1987
What part of speech is this
"Last year" is a noun phrase consisting of the noun "year" modified by the adjective "last".
It is a compound noun or noun phrase.
The part of speech for "answer" is a noun.
part of speech
The part of speech for this particular word is a noun.
Mr- President - 1987 Freedom of Speech 1-4 was released on: USA: 31 May 1987
what part of speech is beneath
adverb