Q: how do I know if my mac is 32 or 64 bit?

Top left corner, click apple,

open about this mac

click on more info...

--- lot of data about your machine here ---

click on system report (or go to utilities/ system report -- its just more fun this way) 

1. Compare your Processor Name to information below
2. determine whether your Mac has a 32-bit or 64-bit processor.
3. all later model macs are 64 bit (unlike ms)

its 64 bit and you don't leave enough specific information for anyone to assist. So go here   everyman.com   and look up your specific model.

What is Intel Core M?

M stands for Mobile.  The Intel Core M is the line of mobile processors for the ultra thin computers.  The 12" MacBook uses the Intel Core M Processor type.

If you are asking whether its 32 or 64bit, then its 64Bit.  Intel has not made a 32Bit processor in several years.

then what about 11.6"?

Darkness Knight wrote:

then what about 11.6"?

The current 11" Macbook Air uses an intel i5 64-bit processor.

The original 11" Macbook Air (Last 2010) used an intel Core 2 Duo 64-bit processor

The Core 2 Duo line was intel's first consumer 64-bit processors.  I think the Xeon commercial line when 64-bit before the Core 2 Duo line.  All the i5 and i7 intel processors are 64-bit.