# Definition:Jevons' Number

## Definition

Jevons' number is the number $8 \, 616 \, 460 \, 799$.

It is $89 \, 681 \times 96 \, 079$.

## Source of Name

This entry was named for William Stanley Jevons.

## Historical Note

In $1874$, William Stanley Jevons made the assertion:

Can the reader say what two numbers multiplied together will produce the number $8616460799$? I think it unlikely that anyone but myself will ever know.

History has shown that if an assertion akin to the above has been made, at least one mathematician will attempt to refute it.

In this case it was Derrick Norman Lehmer who, in $1903$, presented its factorisation to the American Mathematical Society.

A contemporary online integer factorisation tool can do the job in a relative instant.