A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2150720 can be evenly divided by 1 2 4 5 8 10 11 13 16 20 22 26 32 40 44 47 52 55 64 65 80 88 94 104 110 130 143 160 176 188 208 220 235 260 286 320 352 376 416 440 470 517 520 572 611 704 715 752 832 880 940 1,034 1,040 1,144 1,222 1,430 1,504 1,760 1,880 2,068 2,080 2,288 2,444 2,585 2,860 3,008 3,055 3,520 3,760 4,136 4,160 4,576 4,888 5,170 5,720 6,110 6,721 7,520 8,272 9,152 9,776 10,340 11,440 12,220 13,442 15,040 16,544 19,552 20,680 22,880 24,440 26,884 33,088 33,605 39,104 41,360 45,760 48,880 53,768 67,210 82,720 97,760 107,536 134,420 165,440 195,520 215,072 268,840 430,144 537,680 1,075,360 and 2,150,720, with no remainder.
Since 2,150,720 cannot be divided by just 1 and 2,150,720, it is not a prime number.