15804
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
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 40040
- Proper Divisor Sum (Aliquot Sum)
- 24236
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5256
- Möbius Function
- 0
- Radical
- 2634
- Omega Function (Ω)
- 5
- 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
- 76
- 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
- Expansion of (Product_{j>=1} (1-(-x)^j) - 1)^9 in powers of x.at n=24A001487
- Numbers k such that prime(k+3)-(k+3)*tau(k+3) = prime(k-3)-(k-3)*tau(k-3) where tau(k) = A000005(k) is the number of divisors of k.at n=35A067355
- Smallest of 5 consecutive integers divisible respectively by 5 consecutive primes.at n=8A072730
- Numbers m such that there are an equal number of numbers <= m that are contained and that are not contained in the concatenation of terms <= m in A048991.at n=4A105391
- Riordan matrix (1/(x+sqrt(1-4x)),(1-sqrt(1-4x))/(2(x+sqrt(1-4x)))).at n=60A188513
- Number of lower triangles of an n X n 0..5 array with each element unequal to the sum mod 6 of its horizontal and vertical neighbors.at n=2A194502
- T(n,k)=Number of lower triangles of an n X n 0..k array with each element unequal to the sum mod k+1 of its horizontal and vertical neighbors.at n=23A194505
- Numbers n that divide the sum of digits of 36^n.at n=39A220364
- Number of n X 4 0..1 arrays with rows, diagonals and antidiagonals unimodal and columns nondecreasing.at n=13A223834
- Number of tilings of a 6 X n rectangle using integer-sided square tiles of area > 1.at n=23A226370
- Partial sums of A256970.at n=35A256971
- Capless binary boundary codes for holeless strictly non-overlapping polyhexes, only the maximal representative from each equivalence class obtained by rotating.at n=6A258004
- Capless binary boundary codes for fusenes, maximal representative from each equivalence class up to rotation.at n=6A258014
- Numbers n such that the decimal digits of n-phi(n) are a permutation of those of n.at n=33A273799
- Numbers k such that Bernoulli number B_{k} has denominator 1919190.at n=10A295595
- E.g.f. satisfies A(x) = 1/(1 - log(1 + x*A(x)^2)).at n=5A367136