The number 2,786,400 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 18 20 24 25 27 30 32 36 40 43 45 48 50 54 60 72 75 80 81 86 90 96 100 108 120 129 135 144 150 160 162 172 180 200 215 216 225 240 258 270 288 300 324 344 360 387 400 405 430 432 450 480 516 540 600 645 648 675 688 720 774 800 810 860 864 900 1,032 1,075 1,080 1,161 1,200 1,290 1,296 1,350 1,376 1,440 1,548 1,620 1,720 1,800 1,935 2,025 2,064 2,150 2,160 2,322 2,400 2,580 2,592 2,700 3,096 3,225 3,240 3,440 3,483 3,600 3,870 4,050 4,128 4,300 4,320 4,644 5,160 5,400 5,805 6,192 6,450 6,480 6,880 6,966 7,200 7,740 8,100 8,600 9,288 9,675 10,320 10,800 11,610 12,384 12,900 12,960 13,932 15,480 16,200 17,200 17,415 18,576 19,350 20,640 21,600 23,220 25,800 27,864 29,025 30,960 32,400 34,400 34,830 37,152 38,700 46,440 51,600 55,728 58,050 61,920 64,800 69,660 77,400 87,075 92,880 103,200 111,456 116,100 139,320 154,800 174,150 185,760 232,200 278,640 309,600 348,300 464,400 557,280 696,600 928,800 1,393,200 and 2,786,400, with no remainder.
Since 2,786,400 cannot be divided by just 1 and 2,786,400, it is a composite number.