Downloaded a scam app

I got an email from a website pretending to be apple saying that I have 27 viruses on my phone, at the time I did not know it was a scam so I downloaded the app it told me to, once I realised it was a scam I deleted the app immediately but I looked online and it told me that if I downloaded the app it would put new viruses on my phone. What should I do to make sure I do t have a virus on my phone?