It is available on both: Broadcom and many 3rd party sites. The first one perhaps requires some instructions posted here in some threads - do not trust your intuition.
In short: no 32-bit version exists.
A longer story (Windows):
As for 32-bit: It is not and it has "never" been. It has required a 64-bit processor for ages, but there WAS a workflow to install it to 32-bit Windows. It was very, very slow though on 32-bit Windows and even then there were limitations with the processor.
I'm talking now about VMware that runs Guests - a 32-bit application could never do it, not without a major rewrite and even then it would probably be useless (you cannot do much with about 1 GB memory per process and 3+ GB per application). Some parts of the GUI - as somebody else commented just recently - are perhaps 32-bit, but that doesn't mean anything, neither does the installation directory.
In Linux: There hasn't been a requirement for any 32-bit application for ages+ since the processors have been 64-bit much longer than Windows users have realized.