## Definition

Quadrillion is a name for $10^{24}$ in the long scale system:

One quadrillion $= 10^{6 \times 4}$

## Also defined as

In the short scale system:

One quadrillion $= 10^{3 \times 4 + 3} = 10^{15}$

## Historical Note

The British usage of quadrillion to mean $10^{24}$, that is $1 \, 000 \, 000^4$, is no longer used.