706

Number
$706$ (seven hundred and six) is:
 * $2 \times 353$


 * The $36$th Smith number after $4$, $22$, $27$, $58$, $\ldots$, $576$, $588$, $627$, $634$, $636$, $645$, $648$, $654$, $663$, $666$, $690$:
 * $7 + 0 + 6 = 2 + 3 + 5 + 3 = 13$


 * The $23$rd positive integer which cannot be expressed as the sum of a square and a prime:
 * $1$, $10$, $25$, $34$, $58$, $64$, $85$, $91$, $121$, $130$, $169$, $196$, $214$, $226$, $289$, $324$, $370$, $400$, $526$, $529$, $625$, $676$, $706$, $\ldots$


 * The $11$th non-square positive integer which cannot be expressed as the sum of a square and a prime:
 * $10$, $34$, $58$, $85$, $91$, $130$, $214$, $226$, $370$, $526$, $706$, $\ldots$