A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 9478404 can be evenly divided by 1 2 3 4 6 9 12 13 18 26 27 36 39 43 52 54 78 86 108 117 129 156 157 172 234 258 314 351 387 468 471 516 559 628 702 774 942 1,118 1,161 1,404 1,413 1,548 1,677 1,884 2,041 2,236 2,322 2,826 3,354 4,082 4,239 4,644 5,031 5,652 6,123 6,708 6,751 8,164 8,478 10,062 12,246 13,502 15,093 16,956 18,369 20,124 20,253 24,492 27,004 30,186 36,738 40,506 55,107 60,372 60,759 73,476 81,012 87,763 110,214 121,518 175,526 182,277 220,428 243,036 263,289 351,052 364,554 526,578 729,108 789,867 1,053,156 1,579,734 2,369,601 3,159,468 4,739,202 and 9,478,404, with no remainder.
Since 9,478,404 cannot be divided by just 1 and 9,478,404, it is not a prime number.