A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 5287464 can be evenly divided by 1 2 3 4 6 7 8 9 12 13 14 18 21 24 26 27 28 36 39 42 52 54 56 63 72 78 84 91 104 108 117 126 156 168 182 189 216 234 252 269 273 312 351 364 378 468 504 538 546 702 728 756 807 819 936 1,076 1,092 1,404 1,512 1,614 1,638 1,883 2,152 2,184 2,421 2,457 2,808 3,228 3,276 3,497 3,766 4,842 4,914 5,649 6,456 6,552 6,994 7,263 7,532 9,684 9,828 10,491 11,298 13,988 14,526 15,064 16,947 19,368 19,656 20,982 22,596 24,479 27,976 29,052 31,473 33,894 41,964 45,192 48,958 50,841 58,104 62,946 67,788 73,437 83,928 94,419 97,916 101,682 125,892 135,576 146,874 188,838 195,832 203,364 220,311 251,784 293,748 377,676 406,728 440,622 587,496 660,933 755,352 881,244 1,321,866 1,762,488 2,643,732 and 5,287,464, with no remainder.
Since 5,287,464 cannot be divided by just 1 and 5,287,464, it is not a prime number.