The god-icosathol is equal to E100#^^#21 using Cascading-E Notation.[1] The term was coined by Sbiis Saibian.


The name of this number is based on the prefix "god-" (meaning one hyperion at the top cascade level) and the suffix "-icosathol" (meaning cascade level 20).

Approximations in other notations

Notation Approximation
BEAF \(X \uparrow\uparrow 20 \& 100\)
Fast-growing hierarchy \(f_{\omega\uparrow\uparrow21}(100)\)
Hardy hierarchy \(H_{\omega \uparrow \uparrow 22}(100)\)
Slow-growing hierarchy \(g_{\vartheta(\Omega \uparrow \uparrow 21)}(100)\)


  1. Saibian, Sbiis. 4.3.5 Cascading-E NumbersOne to Infinity
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