Googology Wiki
Googology Wiki

Hexafact is the mixed factorial of 6, written as 6*. The term was coined by TechKon. It is equal to \((6,561 \uparrow\uparrow 5) \uparrow\uparrow\uparrow 6\).


The name of this number is based on Greek prefix "hexa-" and the word "factorial".

Approximations in other notations

Notation Approximation
Bird's array notation \(\{\{6561,5,2\},6,3\}\) (exact)
BEAF \(\{\{6561,5,2\},6,3\}\) (exact)
Graham Array Notation \([[6561,5,2],6,3]\) (exact)
Strong Array Notation \(s(s(6561,5,2),6,3)\) (exact)
Hyper-E notation \(E3\#2\#6\)
Chained arrow notation \((6,561 \rightarrow 5 \rightarrow 2) \rightarrow 6 \rightarrow 3\) (exact)
Hyperfactorial array notation \(10!2\)
Nested Factorial Notation \(10![3]\)
Fast-growing hierarchy \(f_4(6)\)
Hardy hierarchy \(H_{\omega^36+\omega^25}(6,561)\)
Slow-growing hierarchy \(g_{\varepsilon_{\zeta_0+1}}(6)\)


SpongeTechX's Googology World

See also