You can download it directly from the site or from here
https://batminer-mobile-mining-farm.en.aptoide.com/

By the way, if you want to mine on computers or GPU, you do not need this app. Just register account and use their new pool
http://pool.batminer.network/?lang=en#getting_started

select one of BATMINER ports in miner settings to connect directly to their network.