12731
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13200
- Proper Divisor Sum (Aliquot Sum)
- 469
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12264
- Möbius Function
- 1
- Radical
- 12731
- 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
- 138
- 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
- A generalized partition function.at n=16A002601
- a(1) = 3; a(n+1) = a(n)-th composite.at n=34A022451
- Concatenation of n-th prime and n in decimal notation.at n=30A075110
- Primonacci numbers: a(n)=a(n-2)+a(n-3)+a(n-5)+a(n-7)+a(n-11)+...+a(n-p(k))+... until n <= p(k), where p(k) is the k-th prime. a(1)=a(2)=1.at n=26A078465
- Expansion of x^2*(-3+4*x)/(1-x^3+x^4).at n=51A110061
- Positive numbers y such that y^2 is of the form x^2+(x+439)^2 with integer x.at n=7A159890
- Integers of the form 4n+3 for which Sum_{i=1..u} J(i,4n+3) obtains value zero exactly 7 times, when u ranges from 1 to (4n+3). Here J(i,k) is the Jacobi symbol.at n=16A166057
- Stack polyominoes with square core.at n=42A188674
- Number of 0..n arrays x(0..3) of 4 elements with zero 3rd differences.at n=33A200155
- Number of (w,x,y) with all terms in {0,...,n} and x != max(|w-x|,|x-y|).at n=23A213496
- Second-order spt function.at n=16A221140
- Difference between pi(10^n) and A226945(n), where pi(x) is the number of primes <= x.at n=12A228724
- Number of palindromic compositions of n into prime parts.at n=52A276420
- Number of separable partitions of n in which the number of distinct (repeatable) parts is 4.at n=45A325648
- Nonnegative numbers k such that, in decimal representation, the subsequence of digits of k^2 occupying an odd position is equal to the digits of k.at n=41A326418
- Numbers k such that both k and k+2 are de Polignac numbers (A006285).at n=15A330284
- Nonnegative numbers k not ending in 0 such that, in decimal representation, the subsequence of digits of k^2 occupying an odd position is equal to the digits of k.at n=16A362020
- Non-palindromic numbers m such that m * repunit of length k is palindromic for all large enough k.at n=51A370053