Thanks for your replies. I wiped out my data from the cluster and also cleared the commitlog before restarting it with num_tokens=256. I then uploaded data using sstableloader.
However, I am still not able to see a uniform distribution of data across nodes of the clusters.
The output of the bin/nodetool -h localhost status commands looks like follows. Some nodes have data as low as 1.12MB while some have as high as 912.57 MB.