A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 2340624 can be evenly divided by 1 2 3 4 6 8 11 12 13 16 22 24 26 31 33 39 44 48 52 62 66 78 88 93 104 121 124 132 143 156 176 186 208 242 248 264 286 312 341 363 372 403 429 484 496 528 572 624 682 726 744 806 858 968 1,023 1,144 1,209 1,364 1,452 1,488 1,573 1,612 1,716 1,936 2,046 2,288 2,418 2,728 2,904 3,146 3,224 3,432 3,751 4,092 4,433 4,719 4,836 5,456 5,808 6,292 6,448 6,864 7,502 8,184 8,866 9,438 9,672 11,253 12,584 13,299 15,004 16,368 17,732 18,876 19,344 22,506 25,168 26,598 30,008 35,464 37,752 45,012 48,763 53,196 60,016 70,928 75,504 90,024 97,526 106,392 146,289 180,048 195,052 212,784 292,578 390,104 585,156 780,208 1,170,312 and 2,340,624, with no remainder.
Since 2,340,624 cannot be divided by just 1 and 2,340,624, it is not a prime number.