A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1315200 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 25 30 32 40 48 50 60 64 75 80 96 100 120 128 137 150 160 192 200 240 274 300 320 384 400 411 480 548 600 640 685 800 822 960 1,096 1,200 1,370 1,600 1,644 1,920 2,055 2,192 2,400 2,740 3,200 3,288 3,425 4,110 4,384 4,800 5,480 6,576 6,850 8,220 8,768 9,600 10,275 10,960 13,152 13,700 16,440 17,536 20,550 21,920 26,304 27,400 32,880 41,100 43,840 52,608 54,800 65,760 82,200 87,680 109,600 131,520 164,400 219,200 263,040 328,800 438,400 657,600 and 1,315,200, with no remainder.
Since 1,315,200 cannot be divided by just 1 and 1,315,200, it is not a prime number.