How can I tell if my installed Android version, not CPU, is a 64 bit or 32 bit one?

As long as a 64 bit CPU is supposed to execute 32 bit programs, it is sometimes hard to know which one do I have installed on my device.

There are programs that require this knowledge, like the Xposed Framework installer.

What could be considered the proper method, whether be it ADB, command-line or software?

I used to do on desktop Linux:

 sudo uname -a

Maybe there is some equivalent for Android?

Further data:

• Some programs that should inform about this are not clear enoguh for me. This is a example of some AIDA64 report. Even when it shows 32 bit, is this info about the operating system? I would say it is just about the hardware:

  
  
  

  _{(Click image to enlarge; my AIDA64 is in Spanish)}

  
  
  

  

Question extended to this other