Does anyone know what this means? like is it a sign?

most days when I look at the time for example on my phone or if I look at the time a message was sent I keep seeing a similar pattern of repeating numbers such as 13:13, 17:17, 21:21. The past few weeks I have noticed it has happened a lot. Does anyone know what this means? I've heard of it being signs for things like being on the right track in life, anyone know any other meanings? Really intrigued!