129 (number)

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

← 128 129 130 →
Cardinalone hundred twenty-nine
Ordinal129th
(one hundred twenty-ninth)
Factorization3 × 43
Divisors1, 3, 43, 129
Greek numeralΡΚΘ´
Roman numeralCXXIX
Binary100000012
Ternary112103
Octal2018
DuodecimalA912
Hexadecimal8116

In mathematicsEdit

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:  ,  ,  , and  .

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.[1]

129 is a repdigit in base 6 (333).

129 is a happy number.[2]

In the militaryEdit

In transportationEdit

  • LZ 129 Hindenburg was a German zeppelin which went up in flames while landing on May 6, 1937
  • London Buses route 129 is a Transport for London contracted bus route in London
  • STS-129 was a Space Shuttle mission to the International Space Station, flown in November 2009 by the shuttle Atlantis.

In other fieldsEdit

129 is also:

See alsoEdit

ReferencesEdit

  1. ^ "Sloane's A016105 : Blum integers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.
  2. ^ "Sloane's A007770 : Happy numbers". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation. Retrieved 2016-05-27.