# 128 (number)

 ← 127 128 129 →
Cardinal one hundred twenty-eight
Ordinal 128th
(one hundred twenty-eighth)
Factorization 27
Divisors 1, 2, 4, 8, 16, 32, 64, 128
Greek numeral ΡΚΗ´
Roman numeral CXXVIII
Binary 100000002
Ternary 112023
Quaternary 20004
Quinary 10035
Senary 3326
Octal 2008
Duodecimal A812
Vigesimal 6820
Base 36 3K36

128 (one hundred [and] twenty-eight) is the natural number following 127 and preceding 129.

## In mathematics

128 is the seventh power of 2. It is the largest number which cannot be expressed as the sum of any number of distinct squares,[1][2] but it is divisible by the total number of its divisors, making it a refactorable number.[3]

The sum of Euler's totient function φ(x) over the first twenty integers is 128.[4]

128 can be expressed by a combination of its digits with mathematical operators thus 128 = 28 - 1, making it a Friedman number in base 10.[5]

A hepteract has 128 vertices.

128 is the only 3-digit number that is a 7th power (27).

## In bar codes

• Code 128 is a Uniform Symbology Specification (USS Code 128) alphanumeric bar code that encodes text, numbers, numerous functions, and designed to encode all 128 ASCII characters (ASCII 0 to ASCII 127), as used in the shipping industry.
• Subdivisions include:

## In other fields

One hundred [and] twenty-eight is also: