Mehectillion is equal to \(10^{3\times 10^{303} + 3}\).[1] It is defined using Sbiis Saibian's generalization of Jonathan Bowers' -illion system. It is the centillionth -illion.


Notation Lower bound Upper bound
Arrow notation \(1000\uparrow(1+10\uparrow303)\)
Down-arrow notation \(1000\downarrow\downarrow102\) \(305\downarrow\downarrow123\)
Steinhaus-Moser Notation 140[3][3] 141[3][3]
Copy notation 2[2[304]] 3[3[304]]
H* function H(H(100))
Taro's multivariable Ackermann function A(3,A(3,1006)) A(3,A(3,1007))
Pound-Star Notation #*((1))*((1))*9 #*((1))*((2))*9
BEAF {1000,1+{10,303}}
Hyper-E notation E(3+3E303)
Bashicu matrix system (0)(1)[31] (0)(1)[32]
Hyperfactorial array notation (167!)! (168!)!
Fast-growing hierarchy \(f_2(f_2(999))\) \(f_2(f_2(1000))\)
Hardy hierarchy \(H_{\omega^22}(999)\) \(H_{\omega^22}(1000)\)
Slow-growing hierarchy \(g_{\omega^{\omega^{\omega^23+3}3+3}}(10)\)


Community content is available under CC-BY-SA unless otherwise noted.