A culture of bacteria has an initial population of 64000 bacteria and doubles every 4 hours. Using the formula P t = P 0 ⋅ 2 t d P t ​ =P 0 ​ ⋅2 d t ​ , where P t P t ​ is the population after t hours, P 0 P 0 ​ is the initial population, t is the time in hours and d is the doubling time, what is the population of bacteria in the culture after 3 hours, to the nearest whole number?