scam phone number?

Many times Malware is misidentified as a Virus, and there is a free program that has been recommended here for detecting Malware. It is called MalwareBytes and although a subscription service is offered, I only recommend the free scan and then delete the program once the scan has been completed. Just click the free download button in the upper right corner and skip any subscription offerings.

https://www.malwarebytes.com

Virus Warning! What to do! - Apple Community

Websites cannot scan your Mac.

Scans are deeply intrusive.

If scanning your Mac were possible, the scammers that created that advertisement would steal everything directly, and not bother with the lies.

Generally: It is also impossible to prove any sufficiently-complex device is not somehow compromised. We can’t tell you that there is no compromise existing. Apple has built-in malware scanning, which makes malware unlikely. But adware snd coupon apps and other such apps, and add-on apps including add-on security apps and add-in cleaner apps can also introduce issues, as well.

More: Scam Pop-ups, Scam Viruses, Scam Receipts… - Apple Community

U. S. Federal Trade Commission – How To Spot, Avoid, and Report Tech Support Scams

"Tech support scammers may try to trick you with a pop-up window that appears on your computer screen. It might look like an error message from your operating system or antivirus software, and it might use logos from trusted companies or websites. The message in the window warns you about a security issue on your computer and tells you to call a phone number to get help.

…

If you get this kind of pop-up window on your computer, don’t call the number. Real security warnings and messages will never ask you to call a phone number."

Nothing from a popup is going to identify or install any virus on your computer as long as you did not click a link to install it. It is a very common scam that needs nothing more than closing the popup. These are more likely on websites that would be deemed less than legitimate to allow these types of advertisements.