user: ### NOW ANSWER:
Question: In what division was there a population density in km2 of 4,491.8 in 2011? 
Columns: ['Administrative division', 'Area (km²) 2011**', 'Population 2001 Census (Adjusted)', 'Population 2011 Census (Adjusted)', 'Population density (/km² 2011)']
Types: ['text', 'text', 'real', 'real', 'text']
Sample row: ['Dhaka District', '1,463.6', 9036647.0, 12517361.0, '8,552.4']
SQL:

assistant: SELECT "Administrative division" FROM "Table" WHERE "Population density (/km² 2011)" = '4,491.8';