I'm going to lose my mind unless I know someone "got" my last post, so I'm going to spoil it here. I also want to improve upon the original idea slightly.
The numbers I listed (0ll0, 0lll00, 0lllll0000, 0lllllll000000, and 0lllllllllllll000000000000) become 6, 28, 496, 8128, and 33550336 in base 10. These are the first five so-called "perfect" numbers, which are integers equal to the sum of all factors besides itself. For example, 6 = 1 + 2 + 3, and 28 = 1 + 2 + 4 + 7 + 14. As best we can tell, all perfect numbers are of the form (2^p - 1)*2^(p - 1), where p is a prime number. This is does not work for *all* prime numbers (it works for a lot of small primes, including 2, 3, 5, 7, 13, 17, 19, but the success rate drops off a cliff after that).
A thing about (2^p - 1)*2^(p - 1) is that when it is written in binary, it becomes (10^p - 1)*10^(p - 1). Interestingly:
p = 2: (10^2 - 1)*10^(2 - 1) = (100 - 1)*10^1 = 11*10 = 110
p = 3: (10^3 - 1)*10^(3 - 1) = (1000 - 1)*10^2 = 111*100 = 11100
p = 5: (10^5 - 1)*10^(5 - 1) = (100000 - 1)*10^4 = 11111*10000 = 111110000
For any perfect number written in binary, it will lead off with p 1s and finish with (p - 1) 0s. Naturally, this makes binary perfect numbers a provocative gender non-binary example: people would at someone and tally many "male" and "female" factors in a row and try to read someone as having that gender, but it'll throw them off when they see a ton of factors in a row the other way.
A quibble is that these numbers have one more 1 than 0 in them, which biases the male side, so I padded the numbers with a 0 in front to balance things out. It is sort of cheating, but binary integers as a whole have one more 1 than 0 digit on average. This is due to numbers not being written with "leading zeros." This helps make our numbers look more compact, but it is akin to writing "1" for male and "0" for female, but skipping all female factors until the first male factor is recorded. This would lead approximately to the same "one extra 1" bias. To undo this effect, adding an extra leading 0 would basically work, but following the nature of the bias, the more proper thing would be to say our binary perfect numbers should be written with n leading zeros 2^(-n-1) of the time. In other words, for the perfect number 11100, we should write:
11100 for 1/2 of people with 11100 at the end
011100 for 1/4 of people with 11100 at the end
0011100 for 1/8 of people with 11100 at the end
00011100 for 1/16 of people with 11100 at the end, and so on.
Considering this modified form is less restrictive, I advocate for it in retrospect.