When you deactivate your account, Twitter saves your information for 30 days in case you decide to reactivate. Your account doesn't show up in your followers' Twitter feeds or internal username searches, but if you reactivate your account within 30 days, your followers are restored.

Twitter's Account Deletion Queue

Twitter puts your account in a queue for permanent deletion to give you time to make sure you want to deactivate. For 30 days, your username is unavailable to use in new accounts, and although it's removed from the Twitter site, it may still turn up in external Web searches. If you reactivate your account, all your account details, including your followers, are restored, although you may not see all your followers on your profile page for up to 24 hours following reactivation. If your follower list is still incomplete 48 hours after you reactivate, contact Twitter support to find out if it can be restored.