-1

Number
$-1$ (minus one) is:


 * The largest strictly negative integer


 * The $1$st integer $n$ such that $\dbinom n 0 + \dbinom n 1 + \dbinom n 2 + \dbinom n 3 = m^2$ for integer $m$:
 * $\dbinom {-1} 0 + \dbinom {-1} 1 + \dbinom {-1} 2 + \dbinom {-1} 3 = 0^2$