Not to be confused with ducentillion.
For the duocentillion by Curt Noll, see Duocentillion (Noll).

The duocentillion is equal to \(10^{309}\).[1] The term was coined by Jonathan Bowers. It is the smallest -illion number not expressible in the double-precision floating-point format, as it maxes out at \(2^{1024}\).

Aarex Tiaokhiao gave the name cetertillion, referring to the value of this number.[2]


Notation Lower bound Upper bound
Scientific notation \(1\times10^{309}\)
Arrow notation \(10\uparrow309\)
Steinhaus-Moser Notation 143[3] 144[3]
Copy notation 9[309] 10[155]
Taro's multivariable Ackermann function A(3,1023) A(3,1024)
Pound-Star Notation #*((608))*11 #*((609))*11
BEAF {10,309}
Hyper-E notation E309
Bashicu matrix system (0)(0)(0)(0)(0)(0)[67317] (0)(0)(0)(0)(0)(0)[67318]
Hyperfactorial array notation 170! 171!
Fast-growing hierarchy \(f_2(1016)\) \(f_2(1017)\)
Hardy hierarchy \(H_{\omega^2}(1016)\) \(H_{\omega^2}(1017)\)
Slow-growing hierarchy \(g_{\omega^{\omega^23+9}}(10)\)

Sources Edit

  1. Illion Numbers
  2. Aarex Tiaokhiao's illion numbers