2789
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 2790
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 2788
- Möbius Function
- -1
- Radical
- 2789
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 128
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 405
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Smallest primitive prime factor of Fibonacci number F(n), or 1 if F(n) has no primitive prime factor.at n=40A001578
- Mixed partitions of n.at n=26A002096
- a(n) = 3*n^2 + 3*n - 1.at n=30A004538
- Coordination sequence T1 for Zeolite Code APD.at n=35A008034
- Coordination sequence T1 for Zeolite Code TON.at n=33A008241
- Twelve iterations of Reverse and Add are needed to reach a palindrome.at n=8A015993
- Numbers k such that the continued fraction for sqrt(k) has period 29.at n=9A020368
- Coordination sequence T3 for Zeolite Code ITE.at n=36A027371
- Primes that are palindromic in base 5.at n=22A029973
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 6.at n=10A031419
- a(n) = prime(10*n - 5).at n=40A031910
- Upper prime of a difference of 12 between consecutive primes.at n=26A031931
- "BFJ" (reversible, size, labeled) transform of 2,1,1,1...at n=8A032039
- Primes of form x^2+41*y^2.at n=19A033228
- a(n) = a(n-1) + a(round(2*(n-1)/3)) + a(round((n-1)/3)) with a(1)=a(2)=1.at n=26A033499
- Multiplicity of highest weight (or singular) vectors associated with character chi_23 of Monster module.at n=33A034411
- a(1)=1, a(n) = smallest odd number such that all sums of pairs of (not necessarily distinct) terms in the sequence are distinct.at n=30A034757
- Number of partitions of n into parts not of the form 11k, 11k+4 or 11k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 4 are greater than 1.at n=31A035947
- Base-5 palindromes that start with 4.at n=23A043009
- Numbers k such that the string 3,8 occurs in the base 9 representation of k but not of k-1.at n=38A044286