A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 756360 can be evenly divided by 1 2 3 4 5 6 8 9 10 11 12 15 18 20 22 24 30 33 36 40 44 45 55 60 66 72 88 90 99 110 120 132 165 180 191 198 220 264 330 360 382 396 440 495 573 660 764 792 955 990 1,146 1,320 1,528 1,719 1,910 1,980 2,101 2,292 2,865 3,438 3,820 3,960 4,202 4,584 5,730 6,303 6,876 7,640 8,404 8,595 10,505 11,460 12,606 13,752 16,808 17,190 18,909 21,010 22,920 25,212 31,515 34,380 37,818 42,020 50,424 63,030 68,760 75,636 84,040 94,545 126,060 151,272 189,090 252,120 378,180 and 756,360, with no remainder.
Since 756,360 cannot be divided by just 1 and 756,360, it is not a prime number.