Question

What kind of noun is several

Answer 1

plural it is talking about multiple things  

Answer 2

i would say it is a count and mass noun. my source (oxford dictionary) said "Nouns can be either countable or uncountable. Countable nouns (or count nouns) are those that refer to something that can be counted. Uncountable nouns (or mass nouns) do not typically refer to things that can be counted and so they do not regularly have a plural form."