aliquot

Aliquot is indeclinable and always plural: ali- (the same vague prefix as aliquis) plus quot, "how many". It never changes for case, gender or number, so aliquot dierum is "of several days" with the ending doing its work on the noun alone. Learners who try aliquoti or aliquotos are inventing forms that do not exist.

In force it sits between paucus and multus: more than a handful, fewer than a crowd, and deliberately unspecific. Latin has a whole ladder here - paucus for few, aliquot for several, nonnullus for a fair number, complures for quite a lot - and writers pick the rung on purpose. Note also the separate adverb aliquotiens, "several times", built on the same stem but a different word.