# Autoencoder and Neural Network Overfitting in terms of parameter number?

I have 1100 sequences for 2 classes. Of them 400 are from one class 1 and 700 are from class 2. I have used an one hidden layer auto-encoder of 2 neurons to capture my features. My initial features are tri-grams for each sequences. So, for each sequence I have 6860 tri-grams. As a result most of my input vectors are sparse vectors.

Now, if I calculate the parameters for this network, I have

6860 * 2 = 13720 paramters (1st layer)
2 * 6860 = 13720 parameters (2nd layer)
-----------------------------------------
27440 parameters (in total)


Now, that is way too many parameters in comparison to my number of data points. Hence, I have used a dropout value of 0.98, on layer 1->hidden layer as well as hidden layer->output layer which makes the number of parameters 13720 * 0.02 = 274 on each layer and in total 548 parameters.

Now, after training, I tried the encoder on my test data of 500 sequences, and extracted the hidden layer of 2 dimensional data. Then I use that data on another 5 neuron single hidden layer neural network to classify. My results are really good in that I am getting around 90% accuracy on my test data which is around the same ball park of the training data accuracy.

My question is am I overfitting in my autoencoder? Am I overfitting by using another neural network? I am worried about my low number of data points. Does my use of dropout seem sensible?

I am worried that I am calculating the parameter numbers wrong, and my network has more parameters than number of data samples even after using Dropout. Does my calculation seem correct?