74HCT595 - IC HCT SERIES, 8-BIT RIGHT SERIAL IN PARALLEL OUT SHIFT REGISTER, TRUE OUTPUT, PDSO16, 3.90 MM, PLASTIC, MS-012, SOT-109-1, SOP-16, Shift Register
The maximum clock frequency for the 74HCT595D,112 is 30 MHz.
Yes, the 74HCT595D,112 is compatible with 3.3V power supply, but the output voltage will be limited to 3.3V.
To ensure that the outputs are in a known state during power-up, you can use an external pull-up or pull-down resistor on the output pins.
The 74HCT595D,112 can sink or source up to 25mA per output pin.
Yes, the 74HCT595D,112 can be used as a level shifter, but it's not recommended as it's not designed for that purpose. A dedicated level shifter IC would be a better choice.