title: Complexity of a simple algorithm to find a prime number
body: <p>I want know if the asymptotic complexity of this simple algorithm to find a prime number is O(n):</p>
  
  <pre><code>PrimeNumber(n)
  Int i;
  If (n%2=0) then { return "not prime"; }
  Else {
    For(i=3;i&lt;(√n)+1;i=i+2;){
      If (n%i=0) then {return "not prime";}
    }     
  }
  return "prime";
  </code></pre>