What does it mean to say that Hinduism has 330 million gods, yet it also

teaches that Brahman is Atman? Do Hindus take that number literally?

How does that explain the Hindu belief that many paths lead to "god"?

It means that Hinduism is a Polytheistic religion. However, according to Hinduism, every god is a manifestation of the ultimate God, Brahman.

Brahman is Atman means that there is no difference between God and the soul of each person. They do not take this number seriously, they believe that the appearance of many gods is due to the veil of illusion of reality.

Since Hindus believe that every god is a manifestation of the One god, they believe that, in the end, every belief is a path toward the One and only god.

Explanation:

In Hinduism there is a diversity of beliefs, but basically the Hindus believe that behind the visible universe (maia) - to which they attribute successive cycles of creation and destruction - is the principle that sustains the universe: Brahman, that absolute that - considered through veil of māyā (the illusion) -, it is God (Īsvara). Leaving the cycle of reincarnations (samsara) and returning to the divine principle constitutes the greatest of all achievements for Hindus.

In the impersonal Hindu current, God is called Brahman. All other beings are His expression, so it is considered the beginning of the universe. This vision can be called monism. It must be distinguished that the impersonal Brahman is the un-personified aspect of God, and it is distinct from Brahma, who is the creator of this universe, but not the "one god." Brahma is a very high incarnate soul that temporarily occupies that position within the material world, but that can fall from its place and be replaced by another soul. Depending on the complexity of each universe, the creative Brahma can have a different number of heads, up to a thousand.

One of the main features of Hinduism is the varied concept of any adorable deity. It recognizes that any person can have a personal conception of Divinity, equally respectable, since God can have all forms, and finally transcends them. Hence the infinity of representations of the Divine. But finally, God is one, although his manifestations are infinite.