12656
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 28272
- Proper Divisor Sum (Aliquot Sum)
- 15616
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5376
- Möbius Function
- 0
- Radical
- 1582
- Omega Function (Ω)
- 6
- Little Omega Function (ω)
- 3
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
- yes
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 81
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = (3*n+1)*(3*n+2).at n=37A001504
- Absolute value of Glaisher's alpha(n).at n=45A002290
- Number of rooted toroidal maps with 3 faces and n vertices and without separating cycles or isthmuses.at n=3A006423
- Number of rooted toroidal maps with 4 faces and n vertices and without separating cycles or isthmuses.at n=2A006424
- Sorted Galois numbers.at n=34A028689
- Product of a prime and the previous number.at n=29A036689
- Open 3-dimensional ball numbers (version 3): a(n) is the number of integer points (i,j,k) contained in an open ball of diameter n, centered at (1/2,1/2,0).at n=29A053595
- Quarter-squared applied twice.at n=30A059403
- a(n) = floor(n^4/64).at n=30A060494
- a(n) = smallest k such that (10^k-1)/9 == 0 mod prime(n)^2, or 0 if no such k exists.at n=29A087094
- Structured tetrakis hexahedral numbers (vertex structure 5).at n=15A100174
- The sum of the next n terms of A114103.at n=13A114105
- Primitive elements of A065607.at n=12A120692
- Elements of A065607 from primitive triples.at n=18A120693
- Numbers k such that k^2 divides 15^k-1.at n=23A128395
- Numbers m such that m^k does not divide the denominator of the m-th generalized harmonic number H(m,k) nor the denominator of the m-th alternating generalized harmonic number H'(m,k), for k = 2.at n=39A128672
- Numbers m such that m^k does not divide the denominator of the m-th generalized harmonic number H(m,k) nor the denominator of the m-th alternating generalized harmonic number H'(m,k), for k = 4.at n=33A128674
- Numbers m such that m^k does not divide the denominator of the m-th generalized harmonic number H(m,k) nor the denominator of the m-th alternating generalized harmonic number H'(m,k), for k = 6.at n=41A128676
- a(n) = floor(n^4/4).at n=15A131479
- a(n) = 25*n^2 + 25*n + 6.at n=22A177059