1804
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 3528
- Proper Divisor Sum (Aliquot Sum)
- 1724
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 800
- Möbius Function
- 0
- Radical
- 902
- Omega Function (Ω)
- 4
- 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
- no
- 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
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- a(n) = (5*n+1)*(5*n+4).at n=8A001545
- Nearest integer to Bernoulli(2n)/(-4n).at n=11A003326
- a(n) = ceiling(Bernoulli(2n)/(-4n)).at n=11A003457
- Numbers k such that k^64 + 1 is prime.at n=17A006316
- Numbers k for which 10k+1, 10k+3, 10k+7 and 10k+9 are primes.at n=15A007811
- Coordination sequence T2 for Zeolite Code ERI.at n=31A008094
- Coordination sequence T3 for Zeolite Code NES.at n=27A008207
- Coordination sequence T7 for Zeolite Code NES.at n=27A008211
- Year of birth of n-th President of U.S.A.at n=13A008745
- Numbers k such that the geometric mean of phi(k) and sigma(k) is an integer.at n=29A011257
- Expansion of 1/((1-3*x)*(1-4*x)*(1-9*x)).at n=3A016909
- Number of lines through exactly 8 points of an n X n grid of points.at n=41A018815
- Numbers whose base-9 representation is the juxtaposition of two identical strings.at n=21A020337
- Numbers k such that the continued fraction for sqrt(k) has period 36.at n=16A020375
- Numbers k such that Fibonacci(k) == 3 (mod k).at n=25A023175
- a(n) = binomial(4n, n) - binomial(4n, n - 3).at n=4A026020
- (d(n)-r(n))/5, where d = A006527 and r is the periodic sequence with fundamental period (4,1,4,0,1).at n=28A026036
- a(n) = n*(n+3).at n=41A028552
- Numbers having period-3 7-digitized sequences.at n=31A031203
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 20.at n=38A031518