A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3782310 can be evenly divided by 1 2 3 5 6 7 10 14 15 21 30 31 35 42 49 62 70 83 93 98 105 147 155 166 186 210 217 245 249 294 310 415 434 465 490 498 581 651 735 830 930 1,085 1,162 1,245 1,302 1,470 1,519 1,743 2,170 2,490 2,573 2,905 3,038 3,255 3,486 4,067 4,557 5,146 5,810 6,510 7,595 7,719 8,134 8,715 9,114 12,201 12,865 15,190 15,438 17,430 18,011 20,335 22,785 24,402 25,730 36,022 38,595 40,670 45,570 54,033 61,005 77,190 90,055 108,066 122,010 126,077 180,110 252,154 270,165 378,231 540,330 630,385 756,462 1,260,770 1,891,155 and 3,782,310, with no remainder.
Since 3,782,310 cannot be divided by just 1 and 3,782,310, it is not a prime number.