A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3440400 can be evenly divided by 1 2 3 4 5 6 8 10 12 15 16 20 24 25 30 40 47 48 50 60 61 75 80 94 100 120 122 141 150 183 188 200 235 240 244 282 300 305 366 376 400 470 488 564 600 610 705 732 752 915 940 976 1,128 1,175 1,200 1,220 1,410 1,464 1,525 1,830 1,880 2,256 2,350 2,440 2,820 2,867 2,928 3,050 3,525 3,660 3,760 4,575 4,700 4,880 5,640 5,734 6,100 7,050 7,320 8,601 9,150 9,400 11,280 11,468 12,200 14,100 14,335 14,640 17,202 18,300 18,800 22,936 24,400 28,200 28,670 34,404 36,600 43,005 45,872 56,400 57,340 68,808 71,675 73,200 86,010 114,680 137,616 143,350 172,020 215,025 229,360 286,700 344,040 430,050 573,400 688,080 860,100 1,146,800 1,720,200 and 3,440,400, with no remainder.
Since 3,440,400 cannot be divided by just 1 and 3,440,400, it is not a prime number.