714

Number
$714$ (seven hundred and fourteen) is:
 * $2 \times 3 \times 7 \times 17$


 * The $21$st integer $n$ after $1$, $3$, $15$, $30$, $35$, $56$, $\ldots$, $210$, $248$, $264$, $357$, $420$, $570$, $616$, $630$ with the property that $\tau \left({n}\right) \mathrel \backslash \phi \left({n}\right) \mathrel \backslash \sigma\left({n}\right)$:
 * $\tau \left({714}\right) = 16$, $\phi \left({714}\right) = 192$, $\sigma \left({714}\right) = 1728$


 * The $1$st of the $5$th (and largest known) pair of consecutive integers whose product is a primorial:
 * $714 \times 715 = 510 \, 510 = 17 \#$


 * The $4$th (? there may be others which are smaller) positive integer after $1$, $7$, $110$ the sum of whose divisors is a cube:
 * $\sigma \left({714}\right) = 1728 = 12^3$


 * Its $\sigma$ value divided by its Euler $\phi$ value is a square:
 * $\dfrac {\sigma \left({714}\right)} {\phi \left({714}\right)} = \dfrac {1728} {192} = 9 = 3^2$

Also see

 * Integers whose Ratio between Sigma and Phi is Square