The UP student number is a unique identifier for a UP student. For example, my own student number was 2018-12497. It indicates I entered the UP system in the year 2018. We also largely refer to someone’s seniority with the same four numbers. Referring to someone’s batch by their year of graduation is uncommon, as (1) batch cohesion is typically present during entry and (2) graduation years are regularly inconsistent within the same batch.
In UP culture
One does not easily disclose their whole student number. Some professors publicly publish grades, with students’ full names obscured with their student number instead. In addition, there’s a culture of mystery (and to a certain point, embarrassment) when someone finds out you’re old, and that can be deduced from one’s student number as well.
Sequential numbers and campus-agnostic
The 12497 part is largely insignificant outside of identification purposes, but I do have a working theory that it is sequential, based on your UPCAT. My peers from high school are proximate to my own number, within the 12400s or the 12500s, as we largely submitted our forms as a batch.
There’s an anecdote on Reddit where two people have consecutive numbers based on their consecutive submission of their UPCAT forms.
The numbers are also campus-agnostic (the same set across all UP System campuses). However, this may change in the future and I can only guarantee its truth during my stay. I also cannot guarantee its truth in the past (say, in the 70s or the 80s).