The Bigrand-exi-hyperillion, coined by SuperJedi224, is equal to HHH16(16)(16)(16), where H(x)=103x+3. Source: [1] "-Illion" numbers by SuperJedi224 Level One Epi-bitillion|Bi-exitillion|En-bitillion|Ex-tritillion|Dek-bitillion|Epi-tritillion|Tre-exitillion|Oct-tritillion|En-tritillion|Ter-exitillion|Pen-exitillion Level Two Hyper-exitillion|Hyper-icositillion|Hyper-bi-exitillion|Hyper-tre-exitillion|Hyper-ter-exitillion|Hyper-pen-exitillion|Hyper-ex-exitillion|Hyper-epi-exitillion|Hyper-oct-exitillion|Hyper-enn-exitillion|Hyper-dek-exitillion Level Three Exitrillion|Exiterillion|Exipetillion|Exitexillion|Exitepillion|Exitokillion|Exinovillion Level Four Hyperillion|Exi-hyperillion|Icosi-hyperillion|Cent-hyperillion Level Five Grand Hyperillion|Grand-exi-hyperillion|G