From a water container, full of water, whose base is in the form of cylinder and on the top a cone shaped structure is mounted over it, water is poured into small hemispherical bowls each of radius is 2.1 cm. Given that radius of cylinder is equals to radius of cone. If the radius and height of the cylinder is 3.5 cm and 8.4 cm, respectively, and the curved surface area of the cone is 40.7 cm², find the minimum number of bowls that would be required to empty the cylindrical vessel.