A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 362880 can be evenly divided by 1 2 3 4 5 6 7 8 9 10 12 14 15 16 18 20 21 24 27 28 30 32 35 36 40 42 45 48 54 56 60 63 64 70 72 80 81 84 90 96 105 108 112 120 126 128 135 140 144 160 162 168 180 189 192 210 216 224 240 252 270 280 288 315 320 324 336 360 378 384 405 420 432 448 480 504 540 560 567 576 630 640 648 672 720 756 810 840 864 896 945 960 1,008 1,080 1,120 1,134 1,152 1,260 1,296 1,344 1,440 1,512 1,620 1,680 1,728 1,890 1,920 2,016 2,160 2,240 2,268 2,520 2,592 2,688 2,835 2,880 3,024 3,240 3,360 3,456 3,780 4,032 4,320 4,480 4,536 5,040 5,184 5,670 5,760 6,048 6,480 6,720 7,560 8,064 8,640 9,072 10,080 10,368 11,340 12,096 12,960 13,440 15,120 17,280 18,144 20,160 22,680 24,192 25,920 30,240 36,288 40,320 45,360 51,840 60,480 72,576 90,720 120,960 181,440 and 362,880, with no remainder.
Since 362,880 cannot be divided by just 1 and 362,880, it is not a prime number.