A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 3677355 can be evenly divided by 1 3 5 9 11 15 17 19 23 33 45 51 55 57 69 85 95 99 115 153 165 171 187 207 209 253 255 285 323 345 391 437 495 561 627 759 765 855 935 969 1,035 1,045 1,173 1,265 1,311 1,615 1,683 1,881 1,955 2,185 2,277 2,805 2,907 3,135 3,519 3,553 3,795 3,933 4,301 4,807 4,845 5,865 6,555 7,429 8,415 9,405 10,659 11,385 12,903 14,421 14,535 17,595 17,765 19,665 21,505 22,287 24,035 31,977 37,145 38,709 43,263 53,295 64,515 66,861 72,105 81,719 111,435 159,885 193,545 216,315 245,157 334,305 408,595 735,471 1,225,785 and 3,677,355, with no remainder.
Since 3,677,355 cannot be divided by just 1 and 3,677,355, it is not a prime number.