17880
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 54000
- Proper Divisor Sum (Aliquot Sum)
- 36120
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4736
- Möbius Function
- 0
- Radical
- 4470
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 48
- 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
- Cubic star numbers: a(n) = n^3 + 4*Sum_{i=0..n-1} i^2.at n=20A051673
- Number of unlabeled 6-gonal cacti having n polygons.at n=7A054368
- Related to enumeration of finite automata.at n=5A064815
- Numbers k such that d(phi(k)) = phi(d(k)), where d=A000005 and phi=A000010.at n=31A078148
- Short leg of primitive Pythagorean triangles having legs that add up to a square, sorted on hypotenuse.at n=22A089547
- Fibonacci(p-J(p,5)) mod p^2, where p is the n-th prime and J is the Jacobi symbol.at n=34A113650
- Numbers n such that sigma(n+sigma(n)) = 4*sigma(n).at n=37A246911
- Number A(n,k) of ordered set partitions of [n] such that for each block b the smallest integer interval containing b has at most k elements; square array A(n,k), n>=0, k>=0, read by antidiagonals.at n=62A276890
- Number of ordered set partitions of [n] such that for each block b the smallest integer interval containing b has at most three elements.at n=7A276893
- Let p = n-th prime == 3 mod 8; a(n) = sum of quadratic nonresidues mod p that are < p/2.at n=26A282724
- Partitions with designated summands in which no parts are multiples of 3.at n=29A293569
- Numbers k such that sigma(k)^k divides k^sigma(k).at n=39A300906
- Indices of unique values in A329152.at n=19A333268
- a(n) = Sum_{i|n, j|n, k|n} lcm(i,j,k).at n=53A344134
- With p = prime(n), a(n) is the least composite k such that A001414(k) = p and k+p is prime, or 0 if there is no such k.at n=37A346501
- Numbers k such that A348215(k) = k.at n=28A348216
- a(n) = 27^n * Sum_{k=0..n} (-1)^k*binomial(-1/3, k)^2.at n=3A367330
- Numbers k such that gcd(2*k^7+1, 3*k^3+2) > 1.at n=15A369153
- a(n) = Sum_{k=1..n} phi(n*k).at n=44A372608