flat number BrE
apartment number AmE

She has to make sure they know her apartment number.

"Do you know the apartment number on the 68th floor?"

Don't know the apartment number, but it's on the second floor.

"All I know is, it has a 618 in the apartment number."

Give them my apartment number in the building and you'll get a discount.

The name "1208" came from the apartment number they first shared.

This town has good number of apartments and the living standards are high.

The number of new apartments and homes went up by only 81,000.

Our gas was turned back on after only 18 days; a number of apartments had to wait another two weeks or more.

A number of apartments are reserved for students with special needs.