129 (number)

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128 129 130
Cardinal one hundred and twenty-nine
Ordinal 129th
(one hundred and twenty-ninth)
Factorization 3 · 43
Divisors 1, 3, 43, 129
Roman numeral CXXIX
Binary 100000012
Ternary 112103
Quaternary 20014
Quinary 10045
Senary 3336
Octal 2018
Duodecimal A912
Hexadecimal 8116
Vigesimal 6920
Base 36 3L36

129 (one hundred [and] twenty-nine) is the natural number following 128 and preceding 130.

In mathematics[edit]

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: 11^2+2^2+2^2, 10^2+5^2+2^2, 8^2+8^2+1^2, and 8^2+7^2+4^2.

129 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).

129 is a happy number.

In the military[edit]

In transportation[edit]

In other fields[edit]

129 is also:

See also[edit]