Is my system able to run 64-bit OS?
If you look at the CPU op-mode(s) line, you'll see a clue:
CPU op-mode(s): 32-bit, 64bitSo yes, your CPU supports 64bit instructions. You can use the 64bit version of Ubuntu if you want to. This will require reinstalling, there is no upgrade path.
Most CPUs you'll encounter —certainly from the last decade or so— will probably support 64bit. This isn't a guarantee because Intel still makes 132 32bit CPUs, however these are super-budget Atoms, Celerons and Pentiums, special-purpose Xeons and a few SoCs. AMD's offerings are similar.
If you can find out what the CPU is (i.e. read the Model name output), you end up with something very Google-able. Here is one of my servers:
Model name: Intel(R) Pentium(R) CPU G3220 @ 3.00GHz
That gives this Intel ARK page which tells you all the CPU features and supported architectures. Of course yours will be different from that link but it's pretty reliable and easier to read then deciphering the flags in lscpu and cat /proc/cpuinfo.
Please, don't be confused from the output.
Architecture: It means whether the current OS installed is 32-bit or 64-bit.
CPU op-mode(s): This is the real output that says as to whether your CPU is 64-bit or not.
To cross-check, from Ubuntu:
lscpu gathers CPU architecture information like number of CPUs, threads, cores, sockets, NUMA nodes, information about CPU caches, CPU family, model, bogoMIPS, byte order and stepping from sysfs and /proc/cpuinfo, and prints it in a human-readable format. It supports both online and offline CPUs. It can also print out in a parsable format, including how different caches are shared by different CPUs, which can be fed to other programs.
So, run the command:
grep "model name" /proc/cpuinfo
you will get the model number of your CPU. Do a google search and there you will find something that says as to whether your CPU is 64-bit or not.
From Intel:
Your CPU supports 64-bit systems.
It can be seen in CPU op-mode(s).