128

Number
$128$ (one hundred and twenty-eight) is:


 * $2^7$


 * In binary:
 * $128_{10} = 10 \, 000 \, 000_2$


 * The $2$nd seventh power after $1$:
 * $128 = 2 \times 2 \times 2 \times 2 \times 2 \times 2 \times 2$


 * The $8$th almost perfect number after $1$, $2$, $4$, $8$, $16$, $32$, $64$:
 * $\sigma \left({128}\right) = 255 = 2 \times 128 - 1$


 * The $1$st positive integer with $7$ or more prime factors:
 * $128 = 2 \times 2 \times 2 \times 2 \times 2 \times 2 \times 2$


 * The $3$rd positive integer after $64, 96$ with $6$ or more prime factors:
 * $128 = 2 \times 2 \times 2 \times 2 \times 2 \times 2 \left({\mathop \times 2}\right)$


 * The $19$th powerful number after $1$, $4$, $8$, $9$, $16$, $25$, $27$, $32$, $36$, $49$, $64$, $72$, $81$, $100$, $108$, $121$, $125$


 * The $5$th and last of the known powers of $2$ whose digits are also all powers of $2$:
 * $1$, $2$, $4$, $8$, $128$


 * The $31$st and largest positive integer which is not the sum of $1$ or more distinct squares:
 * $2$, $3$, $6$, $7$, $8$, $11$, $12$, $15$, $18$, $19$, $22$, $23$, $24$, $27$, $28$, $31$, $32$, $33$, $43$, $44$, $47$, $48$, $60$, $67$, $72$, $76$, $92$, $96$, $108$, $112$, $128$

Also see