The googolseptiplex, googolheptaplex, or googolplexplexplexplexplexplexplex is equal to E100#8 = EEEEEEEE100 in Hyper-E Notation.[1]

It is also equal to \(^{9}10^{2}\) = 1010101010101010100, or one followed by a googolsextiplex (googolplexplexplexplexplexplex) zeros. It is 10101010101010100+1 digits long.

Writing down the full decimal expansion would take 10101010101010100-6 books of 400 pages each, with 2,500 digits on each page.


The name of this number is based on Latin prefix "septi-" and the number "googolplex"

Approximations in other notations

Notation Approximation
Up-arrow notation \(57 \uparrow \uparrow 9\)
Chained arrow notation \(57 \rightarrow 9 \rightarrow 2 \)
Notation Array Notation \((57\{2,2\}9)\)
Hyper-E notation \(E100\#8\)
Hyperfactorial array notation \(12!1\)
BEAF \(\{57,9,2\}\)
Fast-growing hierarchy \(f_3(9)\)
Hardy hierarchy \(H_{\omega^28}(324)\)
Slow-growing hierarchy \(g_{\varepsilon_0}(9)\)


It is likely pronounced as so:


  1. Saibian, Sbiis. Hyper-E Numbers

See also

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