← 102 103 104 →
Cardinalone hundred three
Ordinal103rd
(one hundred third)
Factorizationprime
Prime27th
Greek numeralΡΓ´
Roman numeralCIII
Binary11001112
Ternary102113
Senary2516
Octal1478
Duodecimal8712

103 (one hundred [and] three) is the natural number following 102 and preceding 104.

## In mathematics

103 is a prime number, and the largest prime factor of ${\displaystyle 6!+1=721=7\cdot 103}$.[1] The previous prime is 101. This makes 103 a twin prime.[2] It is the fifth irregular prime,[3] because it divides the numerator of the Bernoulli number ${\displaystyle B_{24}=-{\frac {236364091}{2730))=-{\frac {103\cdot 2294797}{2730)).}$

The equation ${\displaystyle 64^{3}+94^{3}=103^{3}+1}$ makes 103 part of a "Fermat near miss".[4]

There are 103 different connected series-parallel partial orders on exactly six unlabeled elements.[5]

103 is conjectured to be the smallest number for which repeatedly reversing the digits of its ternary representation, and adding the number to its reversal, does not eventually reach a ternary palindrome.[6]

## In science

103 is the atomic number of lawrencium, a radioactive element named after Ernest Lawrence.

## References

1. ^ Sloane, N. J. A. (ed.). "Sequence A002583 (Largest prime factor of n! + 1)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
2. ^ Sloane, N. J. A. (ed.). "Sequence A001097 (Twin primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
3. ^ Sloane, N. J. A. (ed.). "Sequence A000928 (Irregular primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
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