A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5203440 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 16 18 20 22 24 27 30 33 36 40 44 45 48 54 55 60 66 72 73 80 81 88 90 99 108 110 120 132 135 144 146 162 165 176 180 198 216 219 220 240 264 270 292 297 324 330 360 365 396 405 432 438 440 495 528 540 584 594 648 657 660 720 730 792 803 810 876 880 891 990 1,080 1,095 1,168 1,188 1,296 1,314 1,320 1,460 1,485 1,584 1,606 1,620 1,752 1,782 1,971 1,980 2,160 2,190 2,376 2,409 2,628 2,640 2,920 2,970 3,212 3,240 3,285 3,504 3,564 3,942 3,960 4,015 4,380 4,455 4,752 4,818 5,256 5,840 5,913 5,940 6,424 6,480 6,570 7,128 7,227 7,884 7,920 8,030 8,760 8,910 9,636 9,855 10,512 11,826 11,880 12,045 12,848 13,140 14,256 14,454 15,768 16,060 17,520 17,820 19,272 19,710 21,681 23,652 23,760 24,090 26,280 28,908 29,565 31,536 32,120 35,640 36,135 38,544 39,420 43,362 47,304 48,180 52,560 57,816 59,130 64,240 65,043 71,280 72,270 78,840 86,724 94,608 96,360 108,405 115,632 118,260 130,086 144,540 157,680 173,448 192,720 216,810 236,520 260,172 289,080 325,215 346,896 433,620 473,040 520,344 578,160 650,430 867,240 1,040,688 1,300,860 1,734,480 2,601,720 and 5,203,440, with no remainder.
Since 5,203,440 cannot be divided by just 1 and 5,203,440, it is not a prime number.