There are several reasons you might want to verify if your mobile number is associated with a Twitter account:
For any of the above mentioned cases, go to www.twitter.com, and click on the Already using Twitter on your phone? link located on the home page as shown below.
You will be directed to a page where you are asked to enter your phone number. Enter your phone number along with the country code.
If your phone number is linked with any of the Twitter accounts, we will send your phone a text message containing a Verification Code. Use this code to confirm that the number indeed belongs to you!
On the following page, Twitter will ask you to fill in any missing information for your Twitter profile. Your username will already be filled in, and this is how you'll know which account your phone is tied to.
Want to remove your phone from this account? Easy! Read this article for help.