marvin williams wore #24 as a hawk, but obviously had to pick a new number when he came in the july trade because millsap holds that number. marvin's first instinct was to change to #4, but that number is retired for AD, so he chose #2. (note: i think that the actual rules give marvin the right to keep #24 since he has one more year of tenure in the league than millsap, but he's apparently deferring to the guy who has the most tenure wearing #24 HERE.)
when tom gugliotta (a career #24) came to utah in a midseason trade, he chose to take the inverse of his favorite number (#42) instead of force raul lopez to change numbers midseason. when the jazz took gugliotta's contract from the suns, the move enabled them to acquire kirk snyder (who was out of the league at age 24), gordon hayward, and a draft pick that they then traded for a chance to grab ante tomic (who was 24 until this past february). meanwhile, googs wasn't a total salary dump, as the jazz did get 24 starts out of him that year.
pavel podkolzin wore #24 in dallas long enough to play 28 total minutes in his NBA career, during which his grand total of points, rebounds, assists, steals, blocks, turnovers, fouls and field goal attempts was ... 24. the jazz made the pick for the mavericks because they had acquired the 2004 21st pick in the glen rice/john amaechi salary dump trade. they sent it to dallas for a 2005 pick that they packaged to move up for deron williams.