13527
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 20328
- Proper Divisor Sum (Aliquot Sum)
- 6801
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8964
- Möbius Function
- 0
- Radical
- 501
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 37
- 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
- a(n) = prime(n)*(prime(n-1)-1)/2.at n=36A014302
- (s(n)+s(n+1))/6, where s()=A006521.at n=18A016059
- (s(n)+s(n+1))/18, where s()=A006521.at n=23A016060
- Number of partitions of n with equal number of parts congruent to each of 2 and 3 (mod 5).at n=45A035559
- Expansion of (1+x+x^2) / ((1-x)*(1-x-x^2)).at n=17A154691
- Number of ways to place zero or more nonadjacent 0,0 1,0 1,1 2,0 2,1 2,2 3,1 3,2 polyhexes in any orientation on a planar n X n X n triangular grid.at n=7A155356
- Triangle of coefficients of polynomials u(n,x) jointly generated with A210750; see the Formula section.at n=48A210749
- a(n) = round( (e/2)^n ).at n=34A230580
- Position of first occurrence of n in A256918.at n=36A257120
- Expansion of Product_{k>=1} ((1 + x^k)/(1 + x^(3*k)))^k.at n=20A263345
- Balance scale sequence.at n=9A265500
- Total sum of block indices of the elements over all partitions of [n].at n=7A346772
- Numbers k such that k and k+1 are both terms of A365886.at n=41A365887
- Odd binary Niven numbers (A144302) k such that k/wt(k) is also an odd binary Niven number, where wt(k) = A000120(k) is the binary weight of k.at n=34A376618
- a(0) = 1; a(n) = (11*n^2 - 9*n + 4)/2 for n>0.at n=50A389625