According to Sergei Karakayev, Russia has "about 400 launchers with ICBM" in its combat force. This sounds like a nice round number, but it's unlikely to be correct - the number of deployed ICBMs is probably closer to 300 than to 400. It will take some time, though, to get a reasonably good estimate.
Comments
If Russia deploys around 30 new ICBM (RS-24+New Solid Fuel ICBM+Sarmat) a year in next 7 years (upto 2020), the number will be around 300 ICBM provided all the old systems being withdrawn by that time. But it is likely some of the old systems may be in place beyond 2020.
Pavel,
What is the current combined number of operational UR-100MUTTH and R-36M2?