One upside of everyone's name, date of birth, address and personal ID number being public knowledge in Sweden is that organisations don't treat knowing any of those as proof of your identity. It's absurd how that's not the case in other places.
Technically your personal ID is not public knowledge. The first eight digits are, which contain your birth date. The last four digits are always obfuscated. In reality, it is common to provide your personnummer verbally in non-private settings so if someone within earshot had some interest in remembering your ID they could. Edit: The above might not be entirely accurate, check out the thread below. Some of these look…
There are several sites (upplysning.se for example) that show full length of the personal ID. How does that work if it is not public information?