Fzthirteen

Fzthirteen is equal to \(13^{13}\) = \(13\uparrow\uparrow2\) = 302,875,106,592,253

Etymology
Fzthirteen is made out of the Fz- prefix and thirteen, which ends up becoming \(13^{13}\) when concatenated backwards, ergo, 13 to the power of itself.