Question How get my smartphone device camera megapixel?

I'm working with Unity C# and I'm searching for a way to find my exactly device camera megapixel, so I try first with this code:

Code (CSharp):

1.  static WebCamTexture backCam;
2.  
3. void Start()
4. {
5.    if (backCam == null)
6.        backCam = new WebCamTexture();
7.  
8.    GetComponent<Renderer>().material.mainTexture = backCam;
9.  
10.    if (!backCam.isPlaying)
11.        backCam.Play();
12.    float h = backCam.height;
13.    float w = backCam.width;
14.    Debug.Log("The camera pixel is: " + (w * h)/1000000);
15.  
16. }

The result of this code when I execute it in my real phone device was 0.31 however my smartphone camera is 64MP. Is there any idea to get my camera phone resolution ? Thanks.