Amount, when used as a noun, describes a quantity of uncountable nouns, such as air, water, or time.

When used as a noun, number signifies a quantity of countable nouns, such as trees, cities, or papers.

When is  amount used?

Amount, when used as a noun, For instance, We did not have sufficient amount of time to visit the park. As a verb, amount is used with to (amount to); it describes an accumulation of something.  For instance, My bill amounted to $400.

When is  number used?

When used as a noun, For instance, I have to review a number of research papers today. Number is also used as a verb when you want to give a serial number to something or to count something that is typically large in numbers.  For instance, All the seats in the classroom are numbered.