#1 - To mix it into the water and make it easier to mix it into wort.
#2 - To kill off any baddies in the sugar.
You are probably fine on the 2nd account. The first one is total luck at this point I would recommend putting the bottles in a safe container (big tupperware box? cooler?) and handle them with care. Better safe than sorry...
Did you notice a pile of undissolved sugar after you finished bottling? Did you stir the sugar in after dumping it into your beer or just let it fall to the bottom. If you stirred a little you may have mixed it well enough.
That said I would follow Jaycount's advice and put the bottles in something safe. You won't know if you have bombs until you open a few bottles or a few bottles open themselves up.