Is 685 a Prime Number?

To determine whether the number 685 is a prime number, it is necessary to check if it has any divisors besides 1 and itself. This involves checking if there are any other numbers that can divide 685 evenly, meaning without leaving a remainder. If such divisors exist, 685 is not a prime number; otherwise, it would be classified as prime.

To quickly check if 685 is a prime number:

Calculate the square root of 685

$\sqrt{685} = 26.17$

Prime numbers less than or equal to 26.17: 2, 3, 5, 7, 11, 13, 17, 19, 23

• 685 is divisible by number: 5, 137.

Since 685 is divisible by a number 5, 137 other than 1 and itself, so it is not a prime number