What is the ram capacity of roadrunner IBM supercomputer?

Overall system information:

6,480 Opteron processors with 51.8 TiB RAM (in 3,240 LS21 blades)216 System x3755 I/O nodes26 288-port ISR2012 Infiniband 4x DDR switches296 racks2.35 MW power search it on wikipedia for the rest.