1

1 (one) is a positive integer following 0 and preceding 2.

Ordinal form: 1st, first

1 is the multiplicative identity, meaning that \(a = a \times 1\) for all \(a\). In fact, \(a \underbrace{\uparrow\uparrow\ldots\uparrow\uparrow}_n 1 = a\) (arrow notation) for all \(n \geq 1\) and \(a\), so 1 is a sort of identity for all the hyper operators beyond addition. 1 appears frequently as a "default" argument in googological notations, such as BEAF, chained arrow notation, and hyper-E notation.

1 is. It is the only positive integer which is neither prime nor composite.

Sbiis Saibian argued that all numbers larger than 1 are considered "large numbers."