Most people do not want their phone number becoming public knowledge.
For the many out their using WhatsApp there is a concern that your number could be displayed in Google search, so what do you need to do to stop this happening.
If you use WhatsApp’s Click to Chat feature, your phone number may be showing up in Google search results.
Read this great article from Lifehacker for further explanation and a solution
How To Keep Your WhatsApp Number Out Of Google Search Results