A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2037888 can be evenly divided by 1 2 3 4 6 8 9 12 16 18 24 29 32 36 48 58 61 64 72 87 96 116 122 128 144 174 183 192 232 244 261 288 348 366 384 464 488 522 549 576 696 732 928 976 1,044 1,098 1,152 1,392 1,464 1,769 1,856 1,952 2,088 2,196 2,784 2,928 3,538 3,712 3,904 4,176 4,392 5,307 5,568 5,856 7,076 7,808 8,352 8,784 10,614 11,136 11,712 14,152 15,921 16,704 17,568 21,228 23,424 28,304 31,842 33,408 35,136 42,456 56,608 63,684 70,272 84,912 113,216 127,368 169,824 226,432 254,736 339,648 509,472 679,296 1,018,944 and 2,037,888, with no remainder.
Since 2,037,888 cannot be divided by just 1 and 2,037,888, it is not a prime number.