First, take a little time to download an Ohms Law app or Google for an Ohms Law calculator.
Then plug in the numbers you've provided, but realize that the battery - whether it's called a 3.7 or 3.6 V battery is actually 4.2 V at a full charge. The other numbers indicate its nominal voltage, not peak voltage.
Knowing that the AR mod has a standard 510 connection (as opposed to a faux hybrid 510), you'd pull up to 16.8 Amps. That's within the CDR (20A) of your battery.
BEFORE attaching anything to a mech mod, though, it would behoove you to test the atomizer on an ohm meter. There can be a bit of variance in stock coils up to and including fully shorted (rather rare, but it does happen). Once you're quite certain your stock coil is good, you can use it.
Having spouted all that, I never run sub ohm tanks on mech because coils can go from good to bad without warning. I prefer being able to visually check my coils from time to time, and to do that an RDA is preferable.