2048

Number
$1024$ (one thousand and twenty-four) is:
 * $2^{11}$


 * The $11$th power of $2$ after $(1)$, $2$, $4$, $8$, $16$, $32$, $64$, $128$, $256$, $512$, $1024$:
 * $2048 = 2^{11}$


 * The $12$th almost perfect number after $1$, $2$, $4$, $8$, $16$, $32$, $64$, $128$, $256$, $512$, $1024$:
 * $\map {\sigma_1} {2048} = 4095 = 2 \times 2048 - 1$