I have a biological data set with 38 columns and 158 rows. Each row represents one human cell with 38 measured variables. My goal is to find possible clusters within all of my data points. To find the optimal cluster number I used the Silhouette Clustering Method. My optimal number of clusters is 9. To run k means with 9 clusters works fine. But how do I figure out after what variables k means ordered my cells to which cluster?

by definition it must consider all the variables that comprise the observation ... If you asked it to perform over 38 columns, then the answer is all 38 columns

thanks for the answer, but it doesn´t answer my question the way I hoped… I want to find out in what variables my clusters are different. So how can I produce a Dissimilarity / Similarity Matrix in R comparing my clusters with one another?