it has a dual core cpu so it is pretty powerful.
I don't think it worth to try, but i would be interested in the results 
what app is best for mining?
I don't think theres an app for this https://en.bitcoin.it/wiki/Cpu_Miner
You have to compile it.
If your phone has an GPU with openCL (like Ipad2) maybe an GPU miner works too.
https://en.bitcoin.it/wiki/Category:Miners
This made me laugh. Props for getting mining running on your ipad2. Is this available for ipadx? What's your MH/s or KH/s?