The Z80 has about 8500 transistors. To put it into perspective, 64KB of DRAM contains 524288 transistors, as 1 bit of DRAM needs 1 transistor.
Fun fact: an Amstrad CPC equipped with a 4MB RAM expansion has 32 million transistors dedicated to RAM while the Z80 CPU still only have 8500 transistors.
The Z80 comes in a 40-pin DIP package. It has been manufactured in A, B, and C models, differing only in maximum clock speed. It also has been manufactured as a stand-alone microcontroller with various configurations of on-chip RAM and EPROM.