While Google started out as a company that focused solely on Internet search, it has expanded its operations to include other services, such as Google Voice. This service offers you the opportunity to attach multiple cell phone numbers to your Google account. You can choose to use your Google Voice number as the primary number for every phone you own. If you lose your Google Voice number, you can view it once you log in to your Google Voice account.
Go to the Google Voice page. Enter the Gmail address and the associated password you use for Google Voice.
Click "Sign in" to access your Google Voice account.
Look at the top right corner of the screen for "Your Number." The 10-digit number will appear in bold font with the area code in parentheses.