15969
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 21296
- Proper Divisor Sum (Aliquot Sum)
- 5327
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10644
- Möbius Function
- 1
- Radical
- 15969
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 190
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 84.at n=31A031582
- Numbers k such that 221*2^k+1 is prime.at n=35A032487
- a(n) = 2*n^3 - 2*n + 9.at n=19A127989
- Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 01000-11111-00010 pattern in any orientation.at n=11A147018
- Number of n X 6 0..2 arrays with every row and column nondecreasing rightwards and downwards, and the number of instances of each value within one of each other.at n=9A201275
- Odd numbers k such that phi(k) and cototient(k) have the same prime signature.at n=19A280927
- Number of parts in all partitions of n with largest multiplicity eight.at n=29A320378
- Numbers m that generate rotationally symmetrical XOR-triangles T(m) that have central triangles of zeros.at n=21A334769
- a(n) = Sum_{k=1..n} (-1)^(k-1) * binomial(k+3,4) * floor(n/k).at n=26A366939
- a(n) = 10*Fibonacci(n) + (-1)^n.at n=17A372242