Compiler SDK is creating x86 (32-bit) .dll files

I am attempting to compile a 64-bit .dll file using the mcc command in the Compiler SDK. However, the .dll files that are being produced are all 32-bit. I'm running Windows 10 64-bit and MATLAB 2020a (64-bit). Is there a parameter that can be given to the mcc command that can force it to produce 64-bit .dll files?

By the way, I'm checking the .dll by using the windows command "dumpbin /headers Foo.dll" and then reading the output of the "machine" line.