15439
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 15440
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15438
- Möbius Function
- -1
- Radical
- 15439
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 53
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1803
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of binary forests with n nodes.at n=15A003214
- a(n) = C(n+2,3) + C(n,3) + C(n-1,3).at n=31A006004
- Palindromic primes in base 4.at n=40A029972
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=13A031856
- Decimal part of cube root of n starts with 9: first term of runs.at n=23A034135
- Beginning with 3, least prime, greater than the previous term, such that the arithmetic mean of first n terms is a prime.at n=36A090918
- Primes of the form [prime(n)*prime(n+1)+p]/2 with increasing p.at n=37A100558
- a(n)=Prime(a(n-2)+Pi(a(n-1))), where Prime(n) means n-th prime and Pi(n) means number of primes<=n.at n=9A113483
- Prime numbers n such that n^2 +- (n-1) are primes.at n=37A137459
- Primes congruent to 23 mod 47.at n=38A142374
- Primes congruent to 4 mod 49.at n=40A142417
- Primes congruent to 16 mod 53.at n=36A142546
- Primes congruent to 40 mod 59.at n=27A142767
- Primes congruent to 6 mod 61.at n=31A142804
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 2X4 tee 1,1 1,2 1,3 2,3 1,4 in any orientation.at n=8A146045
- Primes p such that p^3 - 12 and p^3 + 12 are also primes.at n=21A153322
- Number of ways to place zero or more nonadjacent 0,0 1,0 2,0 2,1 3,1 3,2 4,2 5,2 polyhexes in any orientation on a planar nXnXn triangular grid.at n=7A155379
- Noncomposite numbers in the western ray of the Ulam spiral as oriented on the March 1964 cover of Scientific American.at n=11A168025
- a(n) = 16*n^2 + 2*n + 1.at n=31A204675
- Let p_(4,3)(m) be the m-th prime == 3 (mod 4). Then a(n) is the smallest p_(4,3)(m) such that the interval(p_(4,3)(m)*n, p_(4,3)(m+1)*n) contains exactly one prime == 3(mod 4).at n=40A210476