Is 1 octillion a number

Yes, 1 octillion is a legitimate number in mathematical nomenclature. In the short scale system (American/modern international usage), octillion equals 10^27—that's 1 followed by 27 zeros. In the long scale system (historical European), octillion equals 10^48.

Like most extremely large named numbers beyond trillion, octillion exists as part of the systematic Latin-based naming convention but has virtually no practical applications. You will never encounter octillion-scale quantities in economics, everyday measurements, or most sciences. Even in cosmology where very large numbers appear, the estimated number of atoms in the observable universe is approximately 10^80—which actually exceeds short-scale octillion but falls short of long-scale octillion. When scientists or mathematicians work with numbers in this range, they invariably use scientific notation (10^27) rather than saying "octillion." These number names exist and are mathematically well-defined, but they function more as linguistic curiosities than practical tools for describing quantities anyone actually encounters or calculates in real-world contexts.