129 (number)

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129 is the natural number following 128 and preceding 130.

Cardinal One hundred [and]
twenty-nine
Ordinal 129th
Factorization 3\cdot43
Roman numeral CXXIX
Binary 10000001
Hexadecimal 81

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[edit] In mathematics

129 is the sum of the first ten prime numbers. It is the smallest number that can be expressed as a sum of three squares in four different ways: 112 + 22 + 22 and 102 + 52 + 22 and 82 + 72 + 42.

However, it is the product of only two primes, 3 and 43, making 129 a semiprime. Since 3 and 43 are both Gaussian primes, this means that 129 is a Blum integer.

129 is a repdigit in base 6 (333).

[edit] In the military

[edit] In transportation

[edit] In other fields

129 is also:

[edit] See also

This page discusses the number 129. For the year, see 129.