In general, the player can know the approximate number of chips. Or you can ask a dealer:captain:
Number of chips anyone has is one example of information that I see as "common knowledge" and anyone should get a truthful answer if asked. How many chips someone has is the same "common knowledge" as who has the button and what the current blinds are. Of course, counting chips is the most asked because it isn't always so clear exactly how many someone has - although close estimates are usually enough I find.
I know a lot of players only ask to get a live read on you, but you are still obligated to respond I feel. Of course, there is nothing stopping you from:
a) politely asking the dealer to count the exact amount or
b) glancing at your stack and giving the truthful answer
If you don't want to give away
tells, then ask the dealer to count them or keeping your stacks organized efficiently and glancing is what I would do. Just stating the number of chips you have doesn't give them much information to go on. What gives them a ton of information is someone handling stacks of chips to get a count: this is why they should be neat enough to glance at to come up with a number quickly.
Example:
Villain: [asks for how many chips I have]
Me: [glance to do the math] "1,210" (or whatever the exact number is).
This doesn't give them much information to work with - other than the chip amount. Anything that is not "common knowledge" of the game (like chip count) then I have the right to ignore them or answer as I see fit.