9156
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 24640
- Proper Divisor Sum (Aliquot Sum)
- 15484
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2592
- Möbius Function
- 0
- Radical
- 4578
- Omega Function (Ω)
- 5
- 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
- 109
- 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
- Magic numbers: atoms with full shells containing any of these numbers of electrons are considered electronically stable.at n=35A018227
- a(n) = (2*n-1)*a(n-1) - a(n-2), a(0) = 0, a(1) = 1.at n=6A053984
- Staircase of coefficients of polynomials used for column g.f.s of triangle A060923.at n=43A061186
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,15.at n=26A064244
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,37.at n=2A064255
- Sum of next a(n) successive primes is a square.at n=7A077280
- a(n) = sigma_3(n) - sigma_1(n).at n=19A092348
- ((Cumulative sum A000045) + (A000079)) - A092176.at n=14A093304
- Numbers k such that k and 8*k, taken together, are zeroless pandigital.at n=35A115932
- Start with 1 and repeatedly reverse the digits and add 52 to get the next term.at n=26A118149
- Triangle read by rows: matrix product of the binomial coefficients with the Stirling numbers of the second kind.at n=32A126350
- Triangle read by rows: A008277 * A007318.at n=31A137597
- Number of walks within N^2 (the first quadrant of Z^2) starting and ending at (0,0) and consisting of n steps taken from {(-1, -1), (-1, 0), (-1, 1), (0, -1), (0, 1), (1, 0)}.at n=9A151368
- 3 times 10-gonal (or decagonal) numbers: a(n) = 3*n*(4*n-3).at n=28A152767
- Numbers n whose square can be represented as a repdigit number in some base less than n.at n=40A158235
- Expansion of 1/(1-4*x-3*x^2-x^3).at n=6A181880
- Meandric numbers for a river crossing up to 9 parallel roads at n points.at n=11A209621
- a(n) = number of n-lettered words in the alphabet {1, 2, 3, 4} with as many occurrences of the substring (consecutive subword) [1, 2] as of [2, 3].at n=7A211308
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x| = 2*|x-y| - |y-z|.at n=28A212578
- Number of primes p such that sqrt(q) - sqrt(p) > 1/n, where q is the prime after p.at n=39A218015