A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2382720 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 17 20 24 30 32 34 40 48 51 60 64 68 73 80 85 96 102 120 128 136 146 160 170 192 204 219 240 255 272 292 320 340 365 384 408 438 480 510 544 584 640 680 730 816 876 960 1,020 1,088 1,095 1,168 1,241 1,360 1,460 1,632 1,752 1,920 2,040 2,176 2,190 2,336 2,482 2,720 2,920 3,264 3,504 3,723 4,080 4,380 4,672 4,964 5,440 5,840 6,205 6,528 7,008 7,446 8,160 8,760 9,344 9,928 10,880 11,680 12,410 14,016 14,892 16,320 17,520 18,615 19,856 23,360 24,820 28,032 29,784 32,640 35,040 37,230 39,712 46,720 49,640 59,568 70,080 74,460 79,424 99,280 119,136 140,160 148,920 158,848 198,560 238,272 297,840 397,120 476,544 595,680 794,240 1,191,360 and 2,382,720, with no remainder.
Since 2,382,720 cannot be divided by just 1 and 2,382,720, it is not a prime number.