Intel Celeron 533
I have another Celeron 533 with the same sSpec number. The one I had didn't work so I decided to go for another CPU. Besides being identical this 533 is made in the 6th week of 2002 which makes it a pretty late model for a Mendocino-core based Celeron. Back in 1998/1999 these were interesting CPU's and in 2000 you'd generally see the last budget iteration. Perhaps Intel continued to make these CPU's for a market that wanted CPU's for their non-FCPGA S370-platform.
533MHz is the fastest Celeron avaiable for the first generation S370 platform. The Coppermine-based CPU's needed a FC-PGA compatible motherboard.