15688
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 30780
- Proper Divisor Sum (Aliquot Sum)
- 15092
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7488
- Möbius Function
- 0
- Radical
- 3922
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 177
- 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 tanh(log(1+tan(x))).at n=8A009773
- a(n) = dot_product(1,2,...,n)*(4,5,...,n,1,2,3).at n=33A026040
- Low temperature series for spin-1/2 Ising specific heat on 2D square lattice, divided by 8.at n=6A029874
- Imaginary part of absolute Gaussian perfect numbers, in order of increasing magnitude.at n=31A102532
- a(n) = 5^n + 2^n - 1^n.at n=6A155588
- First string of 43 consecutive composite numbers.at n=4A177949
- Number of n X n 0..3 arrays with the row and column sums nondecreasing.at n=2A202575
- Number of nX3 0..3 arrays with the row and column sums nondecreasing.at n=2A202577
- T(n,k)=Number of nXk 0..3 arrays with the row and column sums nondecreasing.at n=12A202581
- Number of (n+1)X2 0..4 arrays with the permanents of all 2X2 subblocks equal and nonzero.at n=3A204725
- Number of (n+1)X5 0..4 arrays with the permanents of all 2X2 subblocks equal and nonzero.at n=0A204728
- T(n,k) = Number of (n+1) X (k+1) 0..4 arrays with the permanents of all 2X2 subblocks equal and nonzero.at n=6A204732
- T(n,k) = Number of (n+1) X (k+1) 0..4 arrays with the permanents of all 2X2 subblocks equal and nonzero.at n=9A204732
- a(n) = F(n+7) - (1/2)*(n^3+2*n^2+13*n+26) where F(i) is a Fibonacci number (A000045).at n=15A220888
- 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=39A230358
- Numbers k such that (2*10^k - 179)/3 is prime.at n=14A295394
- Numbers k such that A055228(k)^2 - A055228(k) is a multiple of k, where A055228(k) is ceiling(sqrt(k!)).at n=49A306014
- a(n) is the smallest number k such that the difference between the next prime greater than k and k equals n.at n=38A309877
- Sum of all the parts in the partitions of n into 8 squarefree parts.at n=37A326444
- Even composite integers m such that A004254(m)^2 == 1 (mod m).at n=30A338314