Issue handling CHECKSUM Sql server query c#

I generate CHECKSUM using stored procedure so in short :

Insert into testtable (GtinChecksum) Values(CHECKSUM(@test))
Supposing @test=06949379000409 , generates  Checksum =1024364690

However the same does not match in query in C# ; Supposing as a test i do :

  dbManager.Command.CommandText = @"Select CHECKSUM(@test); ";
  dbManager.Command.Parameters.AddWithValue("@test", '06949379000409');
  string test = dbManager.Command.ExecuteScalar().ToString();

But here CHECKSUM returned = 859561296 that is why it wont match to the above any explanation for this ?