A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 528000 can be evenly divided by 1 2 3 4 5 6 8 10 11 12 15 16 20 22 24 25 30 32 33 40 44 48 50 55 60 64 66 75 80 88 96 100 110 120 125 128 132 150 160 165 176 192 200 220 240 250 264 275 300 320 330 352 375 384 400 440 480 500 528 550 600 640 660 704 750 800 825 880 960 1,000 1,056 1,100 1,200 1,320 1,375 1,408 1,500 1,600 1,650 1,760 1,920 2,000 2,112 2,200 2,400 2,640 2,750 3,000 3,200 3,300 3,520 4,000 4,125 4,224 4,400 4,800 5,280 5,500 6,000 6,600 7,040 8,000 8,250 8,800 9,600 10,560 11,000 12,000 13,200 16,000 16,500 17,600 21,120 22,000 24,000 26,400 33,000 35,200 44,000 48,000 52,800 66,000 88,000 105,600 132,000 176,000 264,000 and 528,000, with no remainder.
Since 528,000 cannot be divided by just 1 and 528,000, it is not a prime number.