Number of the day: 8009

Kari Onni Uolevi Karhunen was born on this day 106 years ago.

Properties of the number 8009:

8009 is a cyclic number.
8009 and 8011 form a twin prime pair.
8009 has 9 antidivisors and 8008 totatives.
8009 has an emirp digit sum 17 in base 10.
8009 has sum of divisors equal to 8010 which is an oblong number.
8009 = 1³ + 2³ + 20³ is the sum of 3 positive cubes in 1 way.
8009 = 4005² - 4004² is the difference of 2 nonnegative squares in 1 way.
8009 is the difference of 2 positive pentagonal numbers in 1 way.
8009 = 28² + 85² is the sum of 2 positive squares in 1 way.
8009 = 17² + 18² + 86² is the sum of 3 positive squares.
8009² = 4760² + 6441² is the sum of 2 positive squares in 1 way.
8009² is the sum of 3 positive squares.
8009 is a proper divisor of 283⁴ - 1.
8009 is an emirp in (at least) the following bases: 2, 4, 11, 18, 23, 26, 29, 31, 35, 38, 41, 46, 49, 50, 63, 65, 67, 71, 76, 81, 84, 85, 87, 89, 91, 92, 93, 94, 96, 97, and 98.
8009 is palindromic in (at least) the following bases: 77, 88, and -91.
8009 in base 36 = 66h and consists of only the digits '6' and 'h'.

The number 8009 belongs to the following On-Line Encyclopedia of Integer Sequences (OEIS) sequences (among others):

Sequence numbers and descriptions below are taken from OEIS.
A002327: Primes of form n^2 - n - 1.
A033274: Primes that do not contain any other prime as a proper substring.
A045714: Primes with first digit 8.
A069675: Primes with either no internal digits or all internal digits are 0.
A081762: Primes p such that p*(p-2) divides 2^(p-1)-1.
A082108: a(n) = 4n^2 + 6n + 1.
A089392: Magnanimous primes: primes with the property that inserting a "+" in any place between two digits yields a sum which is prime.
A136065: Mother primes of order 6.
A247981: Primes dividing nonzero terms in A003095: the iterates of x^2 + 1 starting at 0.
A260147: G.f.: (1/2) * Sum_{n=-oo..+oo} x^n * (1 + x^n)^n, an even function.