A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 576000 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 30 32 36 40 45 48 50 60 64 72 75 80 90 96 100 120 125 128 144 150 160 180 192 200 225 240 250 256 288 300 320 360 375 384 400 450 480 500 512 576 600 640 720 750 768 800 900 960 1,000 1,125 1,152 1,200 1,280 1,440 1,500 1,536 1,600 1,800 1,920 2,000 2,250 2,304 2,400 2,560 2,880 3,000 3,200 3,600 3,840 4,000 4,500 4,608 4,800 5,760 6,000 6,400 7,200 7,680 8,000 9,000 9,600 11,520 12,000 12,800 14,400 16,000 18,000 19,200 23,040 24,000 28,800 32,000 36,000 38,400 48,000 57,600 64,000 72,000 96,000 115,200 144,000 192,000 288,000 and 576,000, with no remainder.
Since 576,000 cannot be divided by just 1 and 576,000, it is not a prime number.