Reinstall Whatsapp. The OTP message will arrive on the given mobile number and WhatsApp will automatically detect it. WhatsApp is free and offers simple secure reliable messaging and calling available on phones all over the world.

After installing the app verify your number and the iCloud ID. If not enter the OTP manually and select Next. Turn on your mobile device and tap Play Store or App Store to launch it.
Uninstall WhatsApp from your Android phone.
Backup WhatsApp Messages to Card. Enter your phone number then tap Next. Quickly send and receive WhatsApp messages right from your computer. Log in to the Google account the one you created the backup with.