Q: Is 643,401 a Prime Number?
A: No, 643,401 is not a prime number.
A prime number is a natural number, greater than one, that can only be divided by 1 and itself.
The number 643401 can be evenly divided by 1 3 9 11 33 67 97 99 201 291 603 737 873 1,067 2,211 3,201 6,499 6,633 9,603 19,497 58,491 71,489 214,467 and 643,401, with no remainder.
Since 643,401 cannot be divided by just 1 and 643,401, it is not a prime number.