720 is Product of Consecutive Numbers in Two Ways/Mistake

Source Work

1997: David Wells: Curious and Interesting Numbers (2nd ed.):

The Dictionary

$720$

Mistake

$10! = 7! \times 6!$, the only known example of a factorial being the product of two other factorials.

Correction

As is pointed out in Factorial as Product of Two Factorials, for all $n \in \Z_{>0}$:

$\paren {n!}! = n! \paren {n! - 1}!$

So the above statement should be amended, for example as is done in the section on the number $10$, to say something like:

Apart from the general rule ...

Sources

• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $720$