12818
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
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 22680
- Proper Divisor Sum (Aliquot Sum)
- 9862
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5376
- Möbius Function
- 1
- Radical
- 12818
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 125
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = 2nd elementary symmetric function of the first n+1 odd positive integers.at n=11A024196
- Numbers k such that k | sigma_6(k).at n=39A055710
- Non-palindromic number and its reversal are both multiples of 17.at n=31A062915
- Indices of primes in the sequence defined by A(0) = 31, A(n) = 10*A(n-1) + 71 for n > 0.at n=16A101844
- Constant term in the reduction by (x^2 -> x+1) of the polynomial F(n+4)*x^n, where F=A000045 (Fibonacci sequence).at n=10A192919
- a(n) = smallest k having at least three prime divisors d such that (d + n) | (k + n).at n=33A202158
- For a polynomial P(m) with rational coefficients, denote by lcmd(P) the LCM of the denominators of all its coefficients. Then a(n) = lcmd(Sum_{i=1..m} (i^n*Sum_{j=1..i} j^n))/ lcmd((Sum_{i=1..m} i^n)^2).at n=42A202533
- Vandermonde sequence using x^2 + y^2 applied to the first n primes.at n=2A203707
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x|=w+|y-z|.at n=34A212685
- Numbers that can be represented as a sum of two distinct nontrivial prime powers in three or more ways.at n=11A225104
- Sum of the squared parts of the partitions of n into exactly two parts.at n=33A226141
- Numbers which are the sum of two squared primes in exactly three ways (ignoring order).at n=4A226562
- Number of (n+1)X(2+1) 0..3 arrays with every element next to itself plus and minus one within the range 0..3 horizontally, vertically or antidiagonally, with no adjacent elements equal.at n=5A232385
- Number of (n+1)X(6+1) 0..3 arrays with every element next to itself plus and minus one within the range 0..3 horizontally, vertically or antidiagonally, with no adjacent elements equal.at n=1A232389
- T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with every element next to itself plus and minus one within the range 0..3 horizontally, vertically or antidiagonally, with no adjacent elements equal.at n=22A232391
- T(n,k)=Number of (n+1)X(k+1) 0..3 arrays with every element next to itself plus and minus one within the range 0..3 horizontally, vertically or antidiagonally, with no adjacent elements equal.at n=26A232391
- Sum of squares of cycle lengths for different cycles in Fibonacci-like sequences modulo n.at n=23A233246
- Numbers k that are the product of four distinct primes such that x^2+y^2 = k has integer solutions.at n=17A248712
- Tribonacci-like sequence a(n) = a(n-1) + a(n-2) + a(n-3) for n >= 3, with a(0) = 1, a(1) = 2, a(2) = 0.at n=17A276658
- Number of degree n products of distinct cyclotomic polynomials.at n=29A280611