2658
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
- 5328
- Proper Divisor Sum (Aliquot Sum)
- 2670
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 884
- Möbius Function
- -1
- Radical
- 2658
- 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
- 53
- 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
- Coordination sequence T2 for Zeolite Code NON.at n=31A008213
- Coordination sequence T3 for Zeolite Code TON.at n=32A008243
- Numbers k such that Fibonacci(k) == -8 (mod k).at n=29A023166
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 50.at n=14A031548
- Dirichlet convolution of 3^(n-1) with Catalan numbers.at n=7A034755
- Number of partitions of n with equal number of parts congruent to each of 0 and 1 (mod 5).at n=38A035552
- Number of partitions of n with equal nonzero number of parts congruent to each of 2, 3 and 4 (mod 5).at n=46A035591
- a(n)=(s(n)+3)/8, where s(n)=n-th base 8 palindrome that starts with 5.at n=30A043069
- Numbers n such that string 7,3 occurs in the base 9 representation of n but not of n-1.at n=35A044317
- Numbers n such that string 5,8 occurs in the base 10 representation of n but not of n-1.at n=29A044390
- Numbers n such that string 7,3 occurs in the base 9 representation of n but not of n+1.at n=35A044698
- Numbers n such that string 5,8 occurs in the base 10 representation of n but not of n+1.at n=29A044771
- Numbers whose base-4 representation contains exactly one 0 and four 2's.at n=28A045046
- Numbers whose base-4 representation contains exactly one 1 and four 2's.at n=31A045094
- 4-wave sequence beginning with 2s.at n=22A060824
- Numbers k such that floor(k*e) is a square.at n=28A062268
- Numbers k such that the number of primes <= k is phi(phi(k)).at n=14A063999
- Numbers n such that f(n) and f(f(n)) are prime, where f(k) = decimal encoding of the prime factorization of k.at n=36A067600
- At these values of k the first, 2nd and 3rd cyclotomic polynomials all give prime numbers.at n=16A070020
- Squarefree numbers sandwiched between a pair of twin primes.at n=24A070195