A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3511404 can be evenly divided by 1 2 3 4 6 9 12 13 18 26 27 36 39 41 52 54 61 78 82 108 117 122 123 156 164 183 234 244 246 351 366 369 468 492 533 549 702 732 738 793 1,066 1,098 1,107 1,404 1,476 1,586 1,599 1,647 2,132 2,196 2,214 2,379 2,501 3,172 3,198 3,294 4,428 4,758 4,797 5,002 6,396 6,588 7,137 7,503 9,516 9,594 10,004 14,274 14,391 15,006 19,188 21,411 22,509 28,548 28,782 30,012 32,513 42,822 45,018 57,564 65,026 67,527 85,644 90,036 97,539 130,052 135,054 195,078 270,108 292,617 390,156 585,234 877,851 1,170,468 1,755,702 and 3,511,404, with no remainder.
Since 3,511,404 cannot be divided by just 1 and 3,511,404, it is not a prime number.