6525
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
- 18
- Divisor Sum
- 12090
- Proper Divisor Sum (Aliquot Sum)
- 5565
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3360
- Möbius Function
- 0
- Radical
- 435
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 137
- 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
- no
- Odd
- yes
Appears in sequences
- Centered icosahedral (or cuboctahedral) numbers, also crystal ball sequence for f.c.c. lattice.at n=12A005902
- a(n) = (2*n - 1)*n^2.at n=15A015237
- Pseudoprimes to base 26.at n=38A020154
- Numerator of n * Product_{d|n} (1 + 1/d).at n=27A029933
- Number of partitions in parts not of the form 11k, 11k+1 or 11k-1. Also number of partitions with no part of size 1 and differences between parts at distance 4 are greater than 1.at n=43A035944
- Absolute value of first differences of A038552, divided by 24.at n=49A038581
- Denominators of continued fraction convergents to sqrt(109).at n=9A041197
- Denominators of continued fraction convergents to sqrt(436).at n=9A041831
- From substitutional generation of Kolakoski sequence (A000002).at n=20A042942
- Odd composite numbers divisible by the sum of their prime factors (counted with multiplicity).at n=23A046347
- a(n) = Sum_{k=1..n} lcm(n,k).at n=24A051193
- 18-gonal (or octadecagonal) numbers: a(n) = n*(8*n-7).at n=29A051870
- Least k for which the integers floor(2k/(m*(m+1))) for m=1,2,...,n are distinct.at n=33A054064
- n is odd and sum of digits of n equals the numbers of divisors of n.at n=33A057532
- a(n) = 280*binomial(n+4,9) + 280*binomial(n+4,8) + 105*binomial(n+3,7) + 77*binomial(n+3,6) + 43*binomial(n+2,5) - 16*binomial(n+2,4) + 20*binomial(n+1,3) - floor(n*(n^2 - 1)*(n^2 - 4)*(n-3)/360).at n=5A064204
- Define C(n) by the recursion C(0) = 6*i where i^2 = -1, C(n+1) = 1/(1 + C(n)), then a(n) = 6*(-1)^n/Im(C(n)) where Im(z) denotes the imaginary part of z.at n=7A069963
- (Sum of digits of n)^4 - (sum of digits of n^4).at n=36A069978
- a(n) = n*(n+2)*(n-2)/3.at n=25A077415
- Minimal (positive) solution a(n) of Pell equation b(n)^2 - D(n)*a(n)^2 = +4 with D(n)= A077425(n). The companion sequence is a(n)=A077428(n).at n=22A078355
- a(n) = floor(average of first n cubes).at n=28A078618