how many units does the landmark condiminium have

The Landmark condominium has 396 units.

Quick Scoop

The clearest property listings for The Landmark in Singapore state that it is a 39-storey condominium with a total of 396 units.

A related launch article also notes the development as having 396 units, which matches the project details above.

Extra note

There is also a separate property called The Landmark in other locations, so the unit count depends on which one you mean.

TL;DR: The Landmark condo in Singapore has 396 units.