IPv4 addresses are written in base 10 for human users.
The "special" case is supporting network addresses to be written as 10.2932832 ("convenient" for class A's), 172.16.61031 (ditto for B's), or just one big address like 39282329, when we're used to 4 octets separated by dots.
Not every bit of host software supports these cases anymore, as basically their sole remaining use case is as a curiosity or to circumvent bad security controls.
The "special" case is supporting network addresses to be written as 10.2932832 ("convenient" for class A's), 172.16.61031 (ditto for B's), or just one big address like 39282329, when we're used to 4 octets separated by dots.
Not every bit of host software supports these cases anymore, as basically their sole remaining use case is as a curiosity or to circumvent bad security controls.