It is approx 20.87 sq metres.
No, it is not. The two multiples of 75 closest to that number are 32,325 and 32,400.
485,250 is divisible by: 1, 2, 3, 5, 6, 10, 15, 25, 30, 50, 75, 125, 150, 250, 375, 647, 750, 1294, 1941, 3235, 3882, 6470, 9705, 16175, 19410, 32350, 48525, 80875, 97050, 161750, 242625, 485250.