If you delete your Tumblr account, your primary blog and all secondary blogs are deleted as well. You are also removed from group blogs immediately after you delete the account. Deleting the primary blog also deletes the entire Tumblr account, which means that all your other blogs are deleted along with the primary blog. You can delete secondary blogs without having to delete the primary blog or the entire account.

Can You Get It Back?

You can't reactivate or recover your Tumblr account after you delete it. This means that you can't recover your blogs or blog posts. It also means that you lose all your premium themes, unless you asked Tumblr to move them to another blog. According to Tumblr, the company can't help you restore your blog or recover your data. You can try to claim the old blog URL when you create a new Tumblr account.