A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 883740 can be evenly divided by 1 2 3 4 5 6 10 11 12 13 15 20 22 26 30 33 39 44 52 55 60 65 66 78 103 110 130 132 143 156 165 195 206 220 260 286 309 330 390 412 429 515 572 618 660 715 780 858 1,030 1,133 1,236 1,339 1,430 1,545 1,716 2,060 2,145 2,266 2,678 2,860 3,090 3,399 4,017 4,290 4,532 5,356 5,665 6,180 6,695 6,798 8,034 8,580 11,330 13,390 13,596 14,729 16,068 16,995 20,085 22,660 26,780 29,458 33,990 40,170 44,187 58,916 67,980 73,645 80,340 88,374 147,290 176,748 220,935 294,580 441,870 and 883,740, with no remainder.
Since 883,740 cannot be divided by just 1 and 883,740, it is not a prime number.