Q: Is 421,578 a Prime Number?
A: No, 421,578 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 421578 can be evenly divided by 1 2 3 6 9 18 27 37 54 74 111 211 222 333 422 633 666 999 1,266 1,899 1,998 3,798 5,697 7,807 11,394 15,614 23,421 46,842 70,263 140,526 210,789 and 421,578, with no remainder.
Since 421,578 cannot be divided by just 1 and 421,578, it is not a prime number.