I hoping you understand what standard deviation is, or have taken an advanced statistics class. Otherwise, there's no real point in finding it...
So if you are really interested in it for good reason, I'll lead you through the simple steps that you can use to acquire the deviation yourself.
You know that 1 deviation on each side is 68 percent overall... Because the left half of the bell curve is ENTIRELY included in the percentile calculation, you have 50 percent already included. To find the 1 standard deviation mark, you would have to know 50 + 1/2 (68) = 84.
Then... find what score corresponds to the 84th percentile. Take this score and subtract the mean (1511)... to get... 1 deviation!
If that made absolutely no sense to you than there's no reason why you should need the STD to begin with.