15855
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
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 29184
- Proper Divisor Sum (Aliquot Sum)
- 13329
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7200
- Möbius Function
- 1
- Radical
- 15855
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 221
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- Expansion of 1/((1-2x)(1-3x)(1-4x)(1-8x)).at n=4A025467
- a(n) = Sum_{i=0..n} Sum_{j=0..i} T(i,j), T given by A026536.at n=11A026550
- Number of permutations of n elements containing a 2-cycle.at n=8A027616
- Numbers whose base-5 representation contains exactly three 0's and three 1's.at n=36A045172
- Numbers with exactly 4 distinct palindromic prime factors.at n=37A046402
- Odd numbers with exactly 4 distinct palindromic prime factors.at n=3A046406
- Smallest i such that i*2^(2)-1, ..., i*2^(n+2)-1 are primes.at n=5A101236
- Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1, 64*k-1 and 128*k-1 are all primes.at n=0A101320
- Numbers k such that 4*k-1, 8*k-1, 16*k-1 and 32*k-1 are all primes.at n=9A101794
- Numbers k such that 4*k-1, 8*k-1, 16*k-1, 32*k-1 and 64*k-1 are all primes.at n=2A101994
- a(n) = 441*n^2 - 21.at n=5A145678
- a(n) = 36*n^2 - n.at n=20A157286
- A partition product of Stirling_1 type [parameter k = -5] with biggest-part statistic (triangle read by rows).at n=22A157385
- A partition product of Stirling_1 type [parameter k = 5] with biggest-part statistic (triangle read by rows).at n=22A157395
- A partition product of Stirling_2 type [parameter k = -5] with biggest-part statistic (triangle read by rows).at n=22A157397
- A partition product of Stirling_2 type [parameter k = 5] with biggest-part statistic (triangle read by rows).at n=22A157405
- Numbers n such that n^6 + 272 is prime.at n=19A161998
- Number of (n+2) X 5 0..1 matrices with each 3 X 3 subblock idempotent.at n=15A224554
- Number of Dyck paths of semilength n avoiding the pattern U^4 D^4 U D.at n=21A225691
- Triangular array read by rows. T(n,k) is the number of 2 tuple lists of length n that have exactly k coincidences; n >= 0, 0 <= k <= n.at n=31A226780