I rarely need to inspect the contents of binaries on Windows, but every time I do I forget the name of the command for doing so! This is a command akin to objdump in the GNU/Linux world, and it is called dumpbin.
It is located in the directory: “C:/Program Files (x86)/Microsoft Visual Studio 9.0/VC/bin/amd64/”.
The option which will print out information as to whether the executable is 32 or 64-bit is /HEADERS. The desired information will be near the top of the output and will read x86 or x64 respectively.