user: Question: Name the guest for 1.64m ratings
Columns: ['Episode', 'Broadcast date', 'Guest(s)', 'Singer(s)', 'Comedian', 'Ratings']
Types: ['real', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '22July2011', 'Matt Lucas', 'The Script', 'Nina Conti', '2.08m']
SQL:

assistant: SELECT "Guest(s)" FROM "Table" WHERE "Ratings" = '1.64m';