39 (
thirty-nine) is the
natural number following
38 and preceding
40.
In mathematics
39 is the 12th distinct
semiprime and the
4th in the {3.q} family. It is the last member of the third
distinct biprime pair (
38,39).
Thirty-nine is the sum of five consecutive primes
(3 + 5 + 7 + 11 + 13) and the sum of the first three powers of
3 (3^1 + 3^2 + 3^3). Given 39, the
Mertens function returns
0 .
39 is the smallest integer which has three partitions into three
parts which all give the same product when multiplied: {25, 8, 6},
{24, 10, 5}, {20, 15, 4}.
39 has an
aliquot sum of
17 which is itself a prime. 39 is the 4th member of the
17-aliquot tree
The thirteenth
Perrin number is 39,
which comes after 17, 22, 29 (it is the sum of the first two
mentioned).
Since the greatest prime factor of 39
^{2} + 1 = 1522 is
761, which is obviously more than 39 twice, 39 is a
StÃ¸rmer number.
According to David Wells in
The Penguin Dictionary of Curious
and Interesting Numbers, 39 is the smallest
mathematically uninteresting
number. The book claims that it is also the first number that
is simultaneously both interesting and uninteresting, thereby
avoiding the paradox.
In science
Astronomy
In religion
In other fields
- Arts and entertainment
- History
- The number of signers to the United States Constitution, out
of 55 members of the Philadelphia Convention delegates
- The traditional number of times citizens of Ancient Rome hit their slaves when beating them, referred to as "Forty save one"
- The
duration, in nanoseconds, of the nuclear reaction in the largest
nuclear explosion ever performed (Tsar bomb)
- The
number of Scud missiles which Iraq fired at
Israel during the Gulf War in
1991
- Other
- At age 39
Historical years
39 A.D.,
39
B.C.,
1939,
2039,
etc.