961

Number
$961$ (nine hundred and sixty-one) is:
 * $31^2$


 * The $12$th square number after $1$, $4$, $36$, $121$, $144$, $256$, $324$, $400$, $576$, $784$, $900$ to be the $\sigma$ (sigma) value of some (strictly) positive integer:
 * $961 = \map \sigma {400}$


 * The $31$st square number after $1$, $4$, $9$, $16$, $25$, $36$, $\ldots$, $625$, $676$, $729$, $784$, $841$, $900$:
 * $961 = 31 \times 31$