You can manage all of your notifications preferences from the Notifications tab of your Account:
You can change the Notification Settings for each calendar you can access.
Email Notification Frequency must be changed to None from the drop down if you do not want to receive an email for specific activities in a calendar. You can also update the frequency of email notifications to hourly, daily, or weekly digest.
Learn more about Notification best practices here.
Are you missing any notifications? Take a look at this troubleshooting article that explains common reasons for missing notifications.