# 9,999,999

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## Number

$9 \, 999 \, 999$ (nine million, nine hundred and ninety-nine thousand, nine hundred and ninety-nine) is:

$3^2 \times 239 \times 4649$

## Historical Note

When John Napier invented what are now known as Napierian logarithms, he assigned the number $10 \, 000 \, 000$ the logarithm $0$, and the number $9 \, 999 \, 999$ the logarithm $1$.

Then, by repeatedly multiplying by $\dfrac {9 \, 999 \, 999} {10 \, 000 \, 000}$, he built the sequence of numbers that had the logarithm $2, 3, 4, \ldots$