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:
 * $2, 3, 6, 7, 8, 11, 12, 15, 18, 19, 22, 23, 24, 27, 28, 31, 32, 33, 43, 44, 47, 48, 60, 67, 72, 76, 92, 96, 108, 112, 128$

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