# isPrime > Test if a number is a prime.
A **prime number** is defined as an integer value greater than `1` which is only divisible by `1` and itself.
## Usage ```javascript var isPrime = require( '@stdlib/math/base/assert/is-prime' ); ``` #### isPrime( x ) Tests if a number is a prime. ```javascript var bool = isPrime( 7.0 ); // returns true ```
## Examples ```javascript var isPrime = require( '@stdlib/math/base/assert/is-prime' ); var bool = isPrime( 11.0 ); // returns true bool = isPrime( 3.14 ); // returns false bool = isPrime( NaN ); // returns false ```