A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 9090432 can be evenly divided by 1 2 3 4 6 8 9 12 13 16 18 24 26 32 36 39 48 52 64 72 78 96 104 117 128 144 156 192 208 234 288 312 384 416 468 576 607 624 832 936 1,152 1,214 1,248 1,664 1,821 1,872 2,428 2,496 3,642 3,744 4,856 4,992 5,463 7,284 7,488 7,891 9,712 10,926 14,568 14,976 15,782 19,424 21,852 23,673 29,136 31,564 38,848 43,704 47,346 58,272 63,128 71,019 77,696 87,408 94,692 116,544 126,256 142,038 174,816 189,384 233,088 252,512 284,076 349,632 378,768 505,024 568,152 699,264 757,536 1,010,048 1,136,304 1,515,072 2,272,608 3,030,144 4,545,216 and 9,090,432, with no remainder.
Since 9,090,432 cannot be divided by just 1 and 9,090,432, it is not a prime number.