I don't know the exact answer to your question because I know nothing about your device other than it is an 8Mbyte device.
An int wouldn't be my choice for an address, because
a) I can't think of many devices with a signed address space
b) if the address is a byte address, then an int would be insufficient on an AVR (you didn't say which processor you were using), though it may be adequate for a page address.