A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3764736 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 19 24 32 36 38 43 48 57 64 72 76 86 96 114 128 129 144 152 171 172 192 228 256 258 288 304 342 344 384 387 456 512 516 576 608 684 688 768 774 817 912 1,032 1,152 1,216 1,368 1,376 1,536 1,548 1,634 1,824 2,064 2,304 2,432 2,451 2,736 2,752 3,096 3,268 3,648 4,128 4,608 4,864 4,902 5,472 5,504 6,192 6,536 7,296 7,353 8,256 9,728 9,804 10,944 11,008 12,384 13,072 14,592 14,706 16,512 19,608 21,888 22,016 24,768 26,144 29,184 29,412 33,024 39,216 43,776 49,536 52,288 58,824 66,048 78,432 87,552 99,072 104,576 117,648 156,864 198,144 209,152 235,296 313,728 418,304 470,592 627,456 941,184 1,254,912 1,882,368 and 3,764,736, with no remainder.
Since 3,764,736 cannot be divided by just 1 and 3,764,736, it is not a prime number.