15687
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 26880
- Proper Divisor Sum (Aliquot Sum)
- 11193
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8856
- Möbius Function
- 0
- Radical
- 1743
- 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
- 146
- Smith Number
- yes
- 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
- Number of set-like atomic species of degree n.at n=42A007650
- a(n) = n*(n-1) + (n-2)*(n-3) + ... + 1*0 + 1 for n odd; otherwise, a(n) = n*(n-1) + (n-2)*(n-3) + ... + 2*1.at n=44A014112
- Odd 10-gonal (or decagonal) numbers.at n=31A028993
- Numbers whose base-5 representation contains exactly three 0's and three 2's.at n=10A045187
- Numbers n such that n + sum of prime factors of n = (n+1) + sum of prime factors of (n+1).at n=18A075654
- Schroeder pseudoprimes: Composites k that divide the k-th Schroeder number A001003(k-1).at n=23A075764
- Sum of largest parts (counted with multiplicity) of all partitions of n.at n=24A092321
- Add/multiply sequence, see example.at n=44A093361
- Row sums of A098546.at n=11A098545
- a(0) = 1, a(n) = 1 + 2*3 + 4*5 + 6*7 + ... + (2n)*(2n+1) for n > 0.at n=22A098931
- 10-gonal numbers for which the sum of the digits is also a 10-gonal number.at n=9A119547
- 10-gonal numbers which are divisible by the sum of their digits.at n=23A119548
- Record values in A046641.at n=33A145771
- First string of 43 consecutive composite numbers.at n=3A177949
- Number of distinct values of the sum of i^2 over 9 realizations of i in 0..n.at n=42A225276
- a(n) is the smallest number k > 0 such that k, k + 1, ... , k + n - 1 are nonprime numbers, but k + n is prime.at n=40A230358
- a(n) = Sum_{i=0..n} digsum(i)^4, where digsum(i) = A007953(i).at n=13A231689
- Least positive integer k such that prime(k*n)+2 = prime(i*n)*prime(j*n) for some 0 < i < j.at n=32A257926
- Let s denote the sum of the deficient numbers in the aliquot parts of x. Sequence lists numbers x such that sigma(s) = usigma(x), where usigma(x) is the sum of the unitary divisors of x (A034448).at n=7A258134
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 397", based on the 5-celled von Neumann neighborhood.at n=28A271691