This looks like a permissions issue in your home directory. To reclaim ownership of the .npm directory execute:
sudo chown -R $(whoami) ~/.npm
whoami is an actual shell command. The backticks around whoami ensure that it gets executed correctly and then placed into the chown command.
you could manually specify your username as well. If your username is "niroj", the command would be
sudo chown -R $(niroj) ~/.npm
Hope it helps!!