Learn Spanish (Spain): Un pueblo no tiene tantos habitantes como una ciudad. - A village doesn't have as many inhabitants as a city.

When you compare quantities using nouns, the word for "as much" or "as many" has to match the gender and number of the noun. Because habitantes (inhabitants) is masculine and plural, we use the masculine plural form tantos.

The English translation says "as many", but what word means "many" in the Spanish sentence?

The word tantos does the job of both "as" and "many" all by itself! When you use tanto/a/os/as with a noun, it means "as much" (if singular) or "as many" (if plural). You do not need to add an extra word for "many".

Is habitantes always masculine?

Words ending in -ante can often be either masculine or feminine depending on who they refer to (for example, el estudiante or la estudiante). However, when we talk about a general, mixed group of people like "inhabitants", Spanish defaults to the masculine plural form los habitantes.

I've seen pueblo used to mean "people". Does it mean "village" here?

Yes! The word pueblo can mean "people" as in a nation or community, but it is also the standard word for a village or small town. Because it is being compared to una ciudad (a city) in this sentence, it is clear that it means "village" here.