Number 27 Appears Daily

Seeing the number 27 as often as you do is likely to be because it is your birth day.

I'm unprepared to comment on whether or not it's an Angel Number. Therefore, I'll stick with Pythagorean numerology.

People are likely to notice certain numbers more than other numbers. The numbers that are noticed most generally are numbers with special personal meaning or with emotional significance.

The why people see certain numbers all the time article talks about that.

Other numbers are also in your life, including in addresses, tags, and phone numbers. But it's 27 that you're noticing and remembering.

Being your birth day, the number 27 has personal meaning. So you're predisposed to noticing its presence. And, as described in the above-linked article, when a person wonders if the fact of seeing a certain number has personal meaning, then the person is likely to see the number even more.