A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5051904 can be evenly divided by 1 2 3 4 6 8 11 12 13 16 22 23 24 26 32 33 39 44 46 48 52 64 66 69 78 88 92 96 104 128 132 138 143 156 176 184 192 208 253 256 264 276 286 299 312 352 368 384 416 429 506 512 528 552 572 598 624 704 736 759 768 832 858 897 1,012 1,056 1,104 1,144 1,196 1,248 1,408 1,472 1,518 1,536 1,664 1,716 1,794 2,024 2,112 2,208 2,288 2,392 2,496 2,816 2,944 3,036 3,289 3,328 3,432 3,588 4,048 4,224 4,416 4,576 4,784 4,992 5,632 5,888 6,072 6,578 6,656 6,864 7,176 8,096 8,448 8,832 9,152 9,568 9,867 9,984 11,776 12,144 13,156 13,728 14,352 16,192 16,896 17,664 18,304 19,136 19,734 19,968 24,288 26,312 27,456 28,704 32,384 35,328 36,608 38,272 39,468 48,576 52,624 54,912 57,408 64,768 73,216 76,544 78,936 97,152 105,248 109,824 114,816 129,536 153,088 157,872 194,304 210,496 219,648 229,632 315,744 388,608 420,992 459,264 631,488 841,984 1,262,976 1,683,968 2,525,952 and 5,051,904, with no remainder.
Since 5,051,904 cannot be divided by just 1 and 5,051,904, it is not a prime number.