As for 11's, there has been some thought, and apparently some research (although how, I'm not sure) about 11, especially 11:11. It tends to represent a mystical occurrance, or perhaps someone from the other side trying to connect with you (e.g. a guardian angel trying to get your attention), or, in some circles, it's the power of 1 (God) repeated 4 times. And it could also mean something negative is happening, or will happen. It is often used in reference to "I saw 11:11 today...something is going to happen!" as in an omen/forwarning of some sort.
One interesting thing to note, however, is that 11:11 was not really discussed/discovered/assigned meaning until we had digital clocks, or clocks without faces and only numbers.
If you think about it, there is no other time of day/night that is a repeating number like this, with 4 identical numbers in a row (and if you're using a 24 hour clock, it only happens once a day instead of twice, but 22:22 happens once, as well). The human mind will find patterns in things which have no pattern, and will assign meanings in things which have no meaning. Thus, we have the whole 11:11 thing, which was not even noted until the clock face had become only numerical and no longer a 'face'.
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