If it's a tablet, then you can do some coding... but don't expect a full-blown development environment.
These days phones don't differ that much, between GalaxyS2 and GalaxyS5 from a regular user standpoint, they only differ with size and speed, that's why I still have an S2 and don't think to change, because there are no phones worth worth buying...
Anyway, one phone to rule them all? no. You played too much Watchdogs.
Basically coding, debugging and terminal on your phone is a joke and fun to show to your friends, but no more practical than a chainsaw dildo.