It says it's got Marvell Armada XP CPUs, which are ARMv7 CPUs, therefore 32-bit instruction set (the 64-bit instruction set was introduced in ARMv8).

The most important question, not addressed anywhere on that page. I'm guessing 32-bit because the 64-bit ARMs were supposed to come out next year.

With 8GB of ram, I'd assume that they are 64bit.