89^8 , electronical computer defeated.

[Accutron]

Assuming that the 'electronic brain' was an IBM 650 (most likely possibility) it would not have been able to produce a 16-digit decimal result. Precision of a 650 was 10 digits with sign. Even after the introduction of floating point hardware in 1955, the 650 would not have been able to handle 89^8 at full precision.