12231
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 18392
- Proper Divisor Sum (Aliquot Sum)
- 6161
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8100
- Möbius Function
- 0
- Radical
- 453
- Omega Function (Ω)
- 5
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 156
- Smith Number
- no
- 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
- no
- Odd
- yes
Appears in sequences
- Egyptian fractions: number of solutions of 1 = 1/x_1 + ... + 1/x_n in positive integers.at n=4A002967
- Stopping times (see Borwein-Loring article for precise definition).at n=7A007176
- Positive numbers k such that k and 2*k are anagrams in base 4 (written in base 4).at n=22A023059
- Number of partitions of n with equal nonzero number of parts congruent to each of 0 and 2 (mod 3).at n=46A035538
- Odd numbers with exactly 5 palindromic prime factors (counted with multiplicity).at n=39A046375
- Let R(i,j) be the rectangle with antidiagonals 1; 2,3; 4,5,6; ...; each k is an R(i(k),j(k)) and A057041(n)=j(F(n)), where F(n) is the n-th Fibonacci number.at n=41A057041
- Numbers n such that n | 12^n + 11^n + 10^n + 9^n + 8^n + 7^n + 6^n + 5^n + 4^n.at n=37A057285
- p such that p^4 + q^4 = r^4 + s^4 = a(n).at n=37A088728
- a(2*n) = 10*a(n), a(2*n+1) = a(n) + a(n+1).at n=46A178569
- Numbers of rank 10 in the poset of lunar numbers.at n=56A191752
- Triangle T(n, k) = Numbers of ways to place k points on a triangular grid of side n so that no two of them are adjacent. Triangle read by rows.at n=27A239567
- Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) > number of parts of p.at n=44A241832
- Partial sums of A073602.at n=35A259035
- Values of a^3 + b^3 such that the equation a^3 + b^3 = x^2 + y^2 + z^2 is not soluble where a, b > 0 and x, y, z >= 0.at n=28A272174
- Triangle read by rows: T(n,k) = number of sequences of n positive integers with reciprocals adding up to k (k=1,2,...,n).at n=10A280519
- Number of ways to place 6 points on a triangular grid of side n so that no two of them are adjacent.at n=4A282998
- Number of 3Xn 0..1 arrays with every element equal to 0, 1, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=12A303315
- Numbers k with exactly two distinct prime factors and such that phi(k) is a square, when: k = p^(2s) * q^(2t+1) with s >= 1, t >= 0, p <> q primes.at n=40A324747
- a(n) is the number of edges formed by n-secting the angles of a nonagon (enneagon).at n=19A335783
- a(n) = Sum_{k=0..floor(n/6)} (-1)^k * binomial(n-3*k,3*k).at n=24A348308