Twenty-twos

Twenty-twos is equal to \(2 \lfloor 10^{20} / 9\rfloor\), or 20 copies of 2:
:22,222,222,222,222,222,222 or hypermathematically by interior superscription as \(2^{18}2\)
:googology
Its prime factorization is 2 × 11 × 41 × 101 × 271 × 3,541 × 9,091 × 27,961.
==Approximations==
Notation 	Lower bound 	Upper bound
Scientific notation 	\(2.222\times10^{19}\) 	\(2.223\times10^{19}\)
Arrow notation 	\(86\uparrow10\) 	\(41\uparrow12\)
Steinhaus-Moser Notation 	16[3] 	17[3]
Copy notation 	2[20] 	2[20]
Taro's multivariable Ackermann function	A(3,61) 	A(3,62)
Pound-Star Notation 	#*(6,4,4)*6 	#*(2,3,2,3)*4
BEAF 	{86,10} 	{41,12}
Hyper-E notation 	2E19 	3E19
Bashicu matrix system 	(0)(0)[68658] 	(0)(0)[68659]
Hyperfactorial array notation 	20! 	21!
Fast-growing hierarchy 	\(f_2(58)\) 	\(f_2(59)\)
Hardy hierarchy 	\(H_{\omega^2}(58)\) 	\(H_{\omega^2}(59)\)
Slow-growing hierarchy 	\(g_{\omega^{\omega+5}10}(12)\)	\(g_{\omega^{\omega+7}4}(11)\)
== Sources ==
== See also ==
Category:Numbers
Category:Class 2
Category:Even numbers
Category:Numbers by André Joyce
Category:Numbers with 7 to 29 digits
Category:Repdigit numbers