Nowadays Android devices are mostly equipped with a 64-bit CPU. 64-bit CPUs support not only 64-bit, but also 32-bit. This gives manufacturers the option to installing a 32-bit instead of a 64-bit operating system on a device with a 64-bit CPU. The difference is not noticeable, but it has a decisive influence on whether applications with 64-bit native libraries can be executed on the device. With this little app you can check if operating system and CPU are 64-bit.
32bit or 64bit
