много/мало/несколько + Genitive Plural

In Russian, indefinite quantifiers (много, мало, немного, несколько) function as the head of a noun phrase. Their behavior depends on the grammatical case and the animacy of the noun. Note that сколько (how many) and столько (so many) follow the exact same declension rules as несколько, and share the same baseline subject-verb agreement rules, though their tendencies differ slightly.

1. Nominative and Inanimate Accusative: The quantifier remains in its base form and requires the noun to be in the genitive plural. For example: много книг (many books).
2. Animate Accusative: When the phrase is a direct object involving people or animals, несколько can either remain in its base form (я видел несколько студентов) or decline to match the genitive (я видел нескольких студентов). Both are acceptable, though the un-declined form is very common. However, много, мало, and немного are strictly indeclinable in the accusative case and always remain in their base form (e.g., я видел много друзей). Note that многих is the animate accusative of the adjective многие (many of the/various), not the quantifier много.
3. Mass Nouns: While несколько is only for countable items (and therefore always takes the genitive plural), много, мало, and немного can be used with uncountable substances, requiring the genitive singular: много воды (much water).
4. Oblique Cases: When the phrase follows a preposition or verb requiring cases like the dative, instrumental, or prepositional, the genitive plural is dropped entirely (with the exception of the distributive по, discussed below). The noun must be in the plural form of whatever oblique case is triggered by the preposition or verb, while the quantifier behaves like an adjective and follows standard adjective agreement rules to match the noun's case (e.g., с несколькими друзьями). Importantly, много, мало, and немного lack oblique forms entirely. For countable nouns, you must switch to the adjectives многие (e.g., со многими друзьями) or немногие. However, be careful: while немного means 'a few' or 'some' (positive), немногие means 'few' or 'not many' (negative). To say 'with a few friends', you should use the oblique forms of несколько instead (с несколькими друзьями). For мало, you often need a workaround like небольшое количество. For uncountable (mass) nouns, these quantifiers cannot be used in oblique cases at all, requiring alternative phrasing (e.g., с большим количеством воды). Note that the stress in несколько remains fixed on the first syllable in all oblique cases (нескольких, нескольким, несколькими).
5. Distributive 'по': With the preposition по, these quantifiers can take special dative forms (по нескольку дней, по многу раз) or remain in the accusative form (по несколько дней, по много раз). Both are perfectly acceptable. However, when using the special dative forms по нескольку and по многу, the noun remains in the genitive plural (e.g., по нескольку часов) and does not decline into the dative plural.
6. Verb Agreement: When a phrase with these quantifiers is the subject, the baseline rule is that the verb takes the neuter singular form. However, plural agreement is also possible when focusing on the individuals as active agents. This is a common choice in predicate agreement with quantified subjects. For много, мало, and сколько, the neuter singular is strongly preferred, even with animate subjects. For несколько, plural agreement is much more common, especially when the subject is animate and actively doing something.

• Пришло много людей (Neuter singular)
• Несколько людей пришли (Plural)