The straight answer is no, it is not, even though everything else of the 2 cameras is the same.  There are several reasons.

(1) An image is 2 dimensional.  Assume 2MP has 2000 x 1000 pixels for horizontal width and vertical height respectively and 4MP is 2000 x 2000. We will see immediately that only the height is doubled and the width stays the same.  Mathematically, the 4MP image picture has a density that is 1.414 times of 2MP and not twice. 

(2) Assume that both cameras have the same size of sensor (and this assumption has a high probability). Divide the sensor area by the number of pixels.  We know immediately that the area per pixel of the 2MP is bigger than 4MP.  If the area is bigger, the amount of light reaching the sensor would be higher and the image would be brighter.  This situation will negate the benefits of a higher number of megapixels.

Nevertheless, we have found that a 4MP camera (K-7211) does provide a higher level of clarity than 1.3MP (T-4201) although we are not able to assign a single figure to describe the improvement.