Teclast (banggood forum) asked for more technical details to pass on to engineers but the following may well be the answer, indicating that 32 bit Android is working on a 64 bit Linux kernel.
Quote from November 2015
What part of Android on Intel Architecture is 64-bit?
Android as released from Google, runs on a Linux kernel. The kernel used by Android on Intel Architecture is a 64-bit kernel. Until Google releases the 64-bit version of Android, Android on Intel Architecture will run 32-bit Android on a 64-bit Linux kernel.
I wonder if Intel sources can confirm this and when it will be corrected. These systems (some) are being advertised as 64 bit Operating System and 64 bit CPU. Purchasers regard Android as the Operating System.
Comment by Xavier H. (Intel), in Android Applications on Intel Architecture Forum
Hi, Most Android devices based on Intel platforms are running a 32bit version of Android with a 64-bit kernel. Apparently it's the case for your Teclast. Hence they can't run 64-bit user-space Android libs. There are still some full x86_64 Android devices, such as the Tesco Hudl 2 and the Chinese version of the Nokia n1. [Tesco, UK supermarket, Hudl is no longer available.
Thank you for sharing this information.