How to check when statistics was last executed?
For your edit - You need to enclose table name into single quotes:

EXEC sp_autostats 'tablename'


and for the original question

First - find the statistics you want to check:



Second - see its properties, and there you will see the last updated timestamp:



Or you may want to execute the following query:

SELECT t.name TableName, s.[name] StatName, STATS_DATE(t.object_id,s.[stats_id]) LastUpdated 
FROM sys.[stats] AS s
JOIN sys.[tables] AS t
    ON [s].[object_id] = [t].[object_id]
WHERE t.type = 'u'