64 bit requirement for mac

Hi,  I have early 2011 MBP.  How do I know if my computer is 64 bit or not.  This is my computer's specification:

Hardware Overview:

  OS X El Capitan V 10.11.5

  Model Name: MacBook Pro

  Model Identifier: MacBookPro8,2

  Processor Name: Intel Core i7

  Processor Speed: 2 GHz

  Number of Processors: 1

  Total Number of Cores: 4

  L2 Cache (per Core): 256 KB

  L3 Cache: 6 MB

  Memory: 8 GB

I need to find out before I purchase LR6. 

Thank you,

Christina