Fzsixty

Fzsixty is equal to \(60^{60}\) = \(60\uparrow\uparrow2\) ≈ \(4.88736\times10^{106}\).

Full decimal expansion:

48873677980689257489322752273774603865660850176000000000000000000000000000000000000000000000000000000000000

Etymology
Fzsixty is made out of the Fz- prefix and sixty, which ends up becoming \(60^{60}\) when concatenated backwards, ergo, 60 to the power of itself.