1800
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 36
- Divisor Sum
- 6045
- Proper Divisor Sum (Aliquot Sum)
- 4245
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 480
- Möbius Function
- 0
- Radical
- 30
- Omega Function (Ω)
- 7
- 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
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 55
- 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
- yes
- Achilles Number
- yes
- Perfect Power
- no
- Smooth Number
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Number of primitive polynomials of degree n over GF(2) (version 2).at n=14A000020
- a(n) = 2*n^2.at n=30A001105
- Number of labeled ordered set partitions into 5 parts for n>=1, a(0)=1.at n=6A001118
- Lah numbers: a(n) = (n-1)*n!/2.at n=4A001286
- Highly abundant numbers: numbers k such that sigma(k) > sigma(m) for all m < k.at n=51A002093
- Pentagonal pyramidal numbers: a(n) = n^2*(n+1)/2.at n=15A002411
- Largest number in n-th row of triangle of Lah numbers (A008297 and A271703).at n=6A002868
- Largest number in n-th row of triangle A019538.at n=6A002869
- a(n) = (2*n + 4) * (1*3*5*...*(2*n+1))^2.at n=2A003955
- Ratios of successive terms are 1,1,2,3,3,4,5,5,6,7,7,...at n=8A004395
- Number of directed animals of size n (k=1 column of A038622); number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| <= 1 for i = 1,2,...,n, where s(0) = 2; also sum of row n+1 of array T in A026323.at n=8A005774
- Expansion of e.g.f. (1 - x)^x.at n=10A007114
- Coordination sequence T3 for Zeolite Code AFO.at n=28A008017
- Coordination sequence T7 for Zeolite Code DDR.at n=26A008077
- Coordination sequence T1 for Zeolite Code ACO, ASV, EDI, and THO.at n=30A008084
- Coordination sequence T4 for Zeolite Code FER.at n=26A008109
- Coordination sequence T6 for Zeolite Code MFS.at n=26A008178
- Coordination sequence T3 for Zeolite Code PAU.at n=31A008221
- Triangle of Lah numbers.at n=16A008297
- Theta series of direct sum of 3 copies of D_4 lattice.at n=2A008659