A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 1395360 can be evenly divided by 1 2 3 4 5 6 8 9 10 12 15 16 17 18 19 20 24 27 30 32 34 36 38 40 45 48 51 54 57 60 68 72 76 80 85 90 95 96 102 108 114 120 135 136 144 152 153 160 170 171 180 190 204 216 228 240 255 270 272 285 288 304 306 323 340 342 360 380 408 432 456 459 480 510 513 540 544 570 608 612 646 680 684 720 760 765 816 855 864 912 918 969 1,020 1,026 1,080 1,140 1,224 1,292 1,360 1,368 1,440 1,520 1,530 1,615 1,632 1,710 1,824 1,836 1,938 2,040 2,052 2,160 2,280 2,295 2,448 2,565 2,584 2,720 2,736 2,907 3,040 3,060 3,230 3,420 3,672 3,876 4,080 4,104 4,320 4,560 4,590 4,845 4,896 5,130 5,168 5,472 5,814 6,120 6,460 6,840 7,344 7,752 8,160 8,208 8,721 9,120 9,180 9,690 10,260 10,336 11,628 12,240 12,920 13,680 14,535 14,688 15,504 16,416 17,442 18,360 19,380 20,520 23,256 24,480 25,840 27,360 29,070 31,008 34,884 36,720 38,760 41,040 43,605 46,512 51,680 58,140 69,768 73,440 77,520 82,080 87,210 93,024 116,280 139,536 155,040 174,420 232,560 279,072 348,840 465,120 697,680 and 1,395,360, with no remainder.
Since 1,395,360 cannot be divided by just 1 and 1,395,360, it is not a prime number.