Windows or Mac?
16-bit app seems very unlikely. Windows setup programs are usually 32-bit and will figure out which 32-bit or 64-bit version of the app to install.
What is the name and extension of this file your downloaded from Amazon.com?
There is definitely a misunderstanding here. Lightroom CC/6 is only available as a 64-bit application. I don't think there has ever been a 16 bit version.