According to this it is 64bit. /
http://www.cpu-world.com/CPUs/Atom/Intel-Atom%20Z2460.html
They could have gotten it wrong.
http://www.realworldtech.com/medfield/2/
"The Saltwell core is a dual-threaded, two issue, in-order, stalling microarchitecture reminiscent of the original Pentium. The instruction set architecture is x86-64 with all the extensions up to and including SSSE3. However, variants optimized for phones will only be available as 32-bit devices, as the memory footprint is limited to 1GB. Versions that are optimized for tablets, low-end notebooks or other form factors that can fit in 2-4GB of memory are likely to have 64-bit support enabled."
David Kanter's comment on phone chips applies to Medfield. The tablet and netbook variants are Clover Trail and Cedar Trail respectively.
You're missing the point. The biggest advantage X86 would have on any platform is in executing legacy x86 applications as native.
The phone bits of a phone are the easy part these days. It is the computer part that the phones do that is hard. It would have made more sense to me for them to put Windows XP on it with a phone skin than to go Android. At least with XP they would have been able to easily load and launch X86 applications - which, again, is an X86 computer/phone's biggest advantage.
By re-compiling and patching Android onto an X86 they will need some form of virtual machine to emulate an ARM CPU and ARM-Android phone environment in order to run the applications in the Google Play store - don't they?
So - as I said. I don't get it. Why go through all of the effort to put an X86 CPU in a phone then cripple it's only real advantage by forcing it to do exactly what all of the other Android phones are doing?
I think you're the one missing the point. Intel didn't make Medfield so that phones could run legacy Windows apps. There's very little market demand for this. Windows XP would suck for doing things that a phone needs to be good at. It doesn't matter how much you in particular might want it; if there's no market demand they won't do it. That should be crystal clear to you.
Intel makes Medfield because Intel wants a piece of the mobile market share, not because Intel is trying to make a new market. Medfield is x86 because Intel makes x86 processors; they have more experience optimizing x86 processor designs, they can leverage existing tools (like for instance validation suites), they don't need to pay licensing costs, and they can better lock in vendors with it.
Android apps already run on a virtual machine called Dalvik, which normally JITs bytecode. Only apps using the NDK execute native code. So yes, ARM NDK binaries are translated to x86 binaries and there's a big performance hit. But NDK is a fat binary format, so you can contain for both ARM and x86 binaries, and usually (unless the app uses platform specific stuff without a portable fallback) there isn't a good reason not to do this anymore. And besides that, a lot of what people run on Android isn't store bought apps but stock stuff like the web browser, media player, mail client, etc. Lack of native ARM support is a disadvantage but not nearly at the scale you're presenting it.