2678
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 4368
- Proper Divisor Sum (Aliquot Sum)
- 1690
- 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
- 1224
- Möbius Function
- -1
- Radical
- 2678
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 27
- 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
- yes
- Odd
- no
Appears in sequences
- Number of connected graphs with n nodes and n+1 edges.at n=9A001435
- Numbers k such that phi(2k-1) < phi(2k), where phi is Euler's totient function A000010.at n=42A001836
- Coordination sequence T1 for Zeolite Code AFT.at n=39A008026
- Coordination sequence T7 for Zeolite Code NES.at n=33A008211
- Coordination sequence T2 for Zeolite Code AFX.at n=39A009865
- Coordination sequence T4 for Zeolite Code VNI.at n=32A009910
- Pisot sequence E(9,17), a(n) = floor( a(n-1)^2/a(n-2) + 1/2 ).at n=9A014004
- Three-fold convolution of primes with themselves.at n=6A014343
- Numbers k such that sigma(k) = sigma(k+13).at n=4A015883
- a(n) is the concatenation of n and 3n.at n=25A019551
- Number of 10's in all partitions of n.at n=35A024794
- a(n) = s(1)*t(n) + s(2)*t(n-1) + ... + s(k)*t(n-k+1), where k = floor(n/2), s = natural numbers, t = odd natural numbers.at n=23A024862
- Partial sums of the sequence of prime powers (A000961).at n=46A024918
- Coordination sequence T2 for Zeolite Code IFR.at n=36A024983
- Index of 7^n within the sequence of the numbers of the form 2^i*7^j.at n=43A025720
- a(n) = (d(n)-r(n))/5, where d = A026060 and r is the periodic sequence with fundamental period (0,0,1,4,0).at n=34A026062
- Number of rooted compound windmills (mobiles) of n nodes with no symmetries.at n=11A032171
- Coordination sequence T2 for Zeolite Code TSC.at n=43A033617
- a(n) = n*(4*n-1).at n=26A033991
- Multiplicity of highest weight (or singular) vectors associated with character chi_165 of Monster module.at n=37A034553