2685
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
- 8
- Divisor Sum
- 4320
- Proper Divisor Sum (Aliquot Sum)
- 1635
- 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
- 1424
- Möbius Function
- -1
- Radical
- 2685
- Omega Function (Ω)
- 3
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 97
- 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+x)*(1-x)^5).at n=16A001752
- Number of equivalence classes of base-3 necklaces of length n, where necklaces are considered equivalent under both rotations and permutations of the symbols.at n=11A002076
- Numbers k such that k and k+1 have same sum of divisors.at n=6A002961
- Coefficients of modular function g_3(tau).at n=5A003297
- a(n) = n*(n + 1)*(2*n^2 + 2*n - 1)/6.at n=8A006324
- Coordination sequence T6 for Zeolite Code EUO.at n=32A008101
- Coordination sequence T1 for Zeolite Code NES.at n=33A008205
- Crystal ball sequence for planar net 3.6.3.6.at n=34A008580
- Coordination sequence T2 for Zeolite Code -CLO.at n=46A009851
- Coordination sequence T4 for Zeolite Code -CLO.at n=45A009853
- Numbers k such that sigma(k) = sigma(k+13).at n=5A015883
- n-th composite is sum of first k composites for some k.at n=50A020642
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = (primes).at n=19A024867
- a(n) = Sum_{k=0..n} T(n,k)*T(n,2n-k), T given by A027960.at n=6A027979
- Numbers k such that 59*2^k+1 is prime.at n=6A032379
- Expansion of 1 / Product_{k >= 1} (1-q^k)^2*(1-q^(11k))^2.at n=14A032442
- Multiplicity of highest weight (or singular) vectors associated with character chi_77 of Monster module.at n=34A034465
- Dirichlet convolution of d(n) (number of divisors) with Fibonacci numbers.at n=17A034772
- Number of partitions of n into parts not of the form 15k, 15k+6 or 15k-6. Also number of partitions with at most 5 parts of size 1 and differences between parts at distance 6 are greater than 1.at n=28A035960
- Numbers k such that string 1,3 occurs in the base 9 representation of k but not of k-1.at n=37A044263