Your task is to check wheter a given integer is a perfect power. If it is a perfect power, return a pair m and k with mk = n as a proof. Otherwise return Nothing, Nil, null, None or your language's equivalent.

Perfect power

var isPP = function(n){
var result=[];
  for (var m=2; m<=Math.sqrt(n); m++)
    {
        var k = 2;
        var p = Math.pow(m, k);
 
        while (p<=n && p>0)
        {
            if (p==n)
                result.push(m,k);
            k++;
            p = Math.pow(m, k);
         }
    }
       while (result.length > 0) {
      return result; 
       }
       return null; 
}