9126
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 21960
- Proper Divisor Sum (Aliquot Sum)
- 12834
- 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
- 2808
- Möbius Function
- 0
- Radical
- 78
- Omega Function (Ω)
- 6
- 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
- 153
- 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
- Pentagonal pyramidal numbers: a(n) = n^2*(n+1)/2.at n=26A002411
- Expansion of Product_{k>=1} (1-x^k)^27.at n=4A010832
- Even pentagonal pyramidal numbers.at n=19A015224
- a(n) = n*(25*n + 1)/2.at n=27A022283
- a(n) = (d(n) - r(n))/5, where d = A026037 and r is the periodic sequence with fundamental period (1,2,0,2,0).at n=49A026039
- a(n) = Sum_{k=0..floor(n/2)} T(n,k), T given by A026747.at n=12A026755
- a(n) = 6*n^2.at n=39A033581
- Denominators of convergents to the comma of Pythagoras.at n=8A046102
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1 and a(2) = a(3) = 3.at n=12A049975
- T(n,3), array T as in A050186; a count of aperiodic binary words.at n=36A050188
- Least k for which the integers Floor(k/(m*(m+1))) for m=1,2,...,n are distinct.at n=29A054061
- Values of m such that N=(am+1)(bm+1)(cm+1) is a 3-Carmichael number (A087788), where a,b,c = 1,2,5.at n=16A064239
- Numbers k such that the sum of the digits of k equals the sum of the prime divisors of k.at n=38A070275
- Multiples of 6 in which there is no common digit in successive terms.at n=25A083494
- a(n) = 4n^3 + 2n^2.at n=12A089207
- A transform of the Jacobsthal numbers.at n=20A099508
- Number of partitions of n such that the number of parts is divisible by the smallest part.at n=32A168657
- a(n) = 13*n*(n+1).at n=26A173307
- Numbers such that the largest prime factor equals the sum of the squares of the other prime factors.at n=45A185077
- Number of (n+1) X (n+1) -4..4 symmetric matrices with every 2 X 2 subblock having sum zero and three distinct values.at n=9A211491