Can I use the Dingtone phone number to register accounts for other apps and websites?

Mostly yes.

It’s understandable that some people expect to have a second phone number as a unique identification just to register accounts on applications or websites so that they can boost their business by holding a separate number to grow potential customers.

In most cases, Dingtone phone numbers can be used to successfully sign up accounts on apps or websites. However, there will be some situations where numbers aren't supported to register on them, which is mostly correlated with the regulation of apps/website (Note: Some apps or websites don’t support SIM-card-free-number registration) to be registered and so on.