A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2549184 can be evenly divided by 1 2 3 4 6 8 11 12 16 17 22 24 32 33 34 44 48 51 64 66 68 71 88 96 102 132 136 142 176 187 192 204 213 264 272 284 352 374 408 426 528 544 561 568 704 748 781 816 852 1,056 1,088 1,122 1,136 1,207 1,496 1,562 1,632 1,704 2,112 2,244 2,272 2,343 2,414 2,992 3,124 3,264 3,408 3,621 4,488 4,544 4,686 4,828 5,984 6,248 6,816 7,242 8,976 9,372 9,656 11,968 12,496 13,277 13,632 14,484 17,952 18,744 19,312 24,992 26,554 28,968 35,904 37,488 38,624 39,831 49,984 53,108 57,936 74,976 77,248 79,662 106,216 115,872 149,952 159,324 212,432 231,744 318,648 424,864 637,296 849,728 1,274,592 and 2,549,184, with no remainder.
Since 2,549,184 cannot be divided by just 1 and 2,549,184, it is not a prime number.