8665
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 25
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10404
- Proper Divisor Sum (Aliquot Sum)
- 1739
- 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
- 6928
- Möbius Function
- 1
- Radical
- 8665
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 140
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 51.at n=13A020390
- a(n) = [ 2nd elementary symmetric function of {sqrt(k+1)} ], k = 1,2,...,n.at n=31A025219
- a(n) = floor(2^n/(n^2)).at n=21A060505
- Sum of n-th row of triangle of primes: 2; 2 3 2; 2 3 5 3 2; 2 3 5 7 5 3 2; ...; where n-th row contains 2n+1 terms.at n=46A061802
- Average of squares of successive primes: a(n) = (prime(n+1)^2 + prime(n)^2)/2, with n >= 2.at n=22A075892
- Total number of parts in all partitions of n into prime parts.at n=49A084993
- Antidiagonal sums of A086272 (and of A086273).at n=19A086274
- a(n) = Sum_{k=1..n} (lcm(n,n-1,...,n-k+2,n-k+1)/lcm(1,2,...,k)).at n=15A093431
- Number of partitions of {1,...,n} containing 4 strings of 3 consecutive integers such that only v-strings of consecutive integers can appear in a block, where v = 1,2,3.at n=3A105494
- a(n) = 361*n + 1.at n=23A158310
- a(n) = 24*n^2 + 1.at n=19A158547
- 1/9 the number of (n+1) X 8 0..2 arrays with all 2 X 2 subblocks having the same four values.at n=11A184046
- Numbers k such that sigma(tau(phi(k))) = phi(tau(sigma(k))).at n=37A226118
- Number of lattice points in the closed region bounded by the graphs of y = (5/6)*x^2, x = n, and y = 0, excluding points on the x-axis.at n=30A227347
- a(n) = 6*n^2 + 1.at n=38A227776
- Number of 3-element subsets of {1,...,n} whose sum has more than 3 divisors.at n=41A241564
- Numbers n such that the sum of the distinct prime factors of prime(n)-1 and prime(n+1)-1 are the same.at n=8A259562
- Expansion of Product_{k>=1} ((1 + x^(2*k))/(1 - x^(2*k-1)))^k.at n=21A295831
- Number of parts in all partitions of n in which no part occurs more than six times.at n=23A320609
- a(1)=1; thereafter, a(n) is the smallest number such that both the addition and multiplication tables for (a(1),...,a(n)) contain n*(n+1)/2 different entries (the maximum possible).at n=62A337655