Your RAM can possibly be overclocked, but maybe not. It's in the luck of the draw. If it's rated at 2133, then that's all that's guaranteed.
To overclock the RAM, keep in mind that the faster you push it, the lower you may have to set the timings. You may also have to bump up the voltage slightly.
Exactly how low for timings and where they should be set and exactly if and how much the voltage should be changed can be different from stick to stick even in the same brand and model of memory. You have to experiment and then test. It takes time and patience.
While there is a great performance increase from 1866MHz to 2133MHz RAM paired with an A10-6800K, the performance increase from 2133MHz to 2400MHz is quite minor, in my personal experience. If you're stable at 2133MHz, I'd leave it alone. There just isn't enough performance gain to make it worthwhile in my personal opinion.