How to check sql server is running which bit (32 or 64 bit) version

by using @@version :

Open SQL Server Management Studio>right click on the DB Server> select New Query

select @@version

Result:

Microsoft SQL Server 2008 R2 (RTM) - 10.50.1617.0 (Intel X86)   Apr 22 2011 11:57:00   Copyright (c) Microsoft Corporation  Developer Edition on Windows NT 6.1 <X64> (Build 7600: ) (WOW64)

 Server Name:

select @@servername

Service Name:

select @@servicename