3689
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 4608
- Proper Divisor Sum (Aliquot Sum)
- 919
- 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
- 2880
- Möbius Function
- -1
- Radical
- 3689
- 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
- 100
- 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
- Numbers k such that 19*2^k - 1 is prime.at n=20A001775
- a(n) = 1000*log(n) rounded to the nearest integer.at n=39A004241
- a(n) = floor(n*phi^10), where phi is the golden ratio, A001622.at n=30A004925
- Expansion of x*(1+x-x^2)/((1-x)^4*(1+x)).at n=33A005744
- Coordination sequence T1 for Zeolite Code LTA and RHO.at n=48A008137
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 4.at n=17A013592
- Number of partitions of 2*n into at most 4 parts.at n=38A014126
- G.f.: (1+x)*(1+x^3)*(1+x^5)*(1+x^7)*(1+x^9)/((1-x^2)*(1-x^4)*(1-x^6)*(1-x^8)*(1-x^10)).at n=54A014670
- Numbers k such that k + sum of its prime factors = (k+1) + sum of its prime factors.at n=16A020700
- Fibonacci sequence beginning 1, 25.at n=12A022395
- Sequence satisfies T(a)=a, where T is defined below.at n=46A027597
- Numbers having period-4 6-digitized sequences.at n=9A031197
- Number of partitions of n into parts not of form 4k+2, 20k, 20k+7 or 20k-7. Also number of partitions in which no odd part is repeated, with at most 3 parts of size less than or equal to 2 and where differences between parts at distance 4 are greater than 1 when the smallest part is odd and greater than 2 when the smallest part is even.at n=41A036027
- Numbers n such that string 8,9 occurs in the base 10 representation of n but not of n-1.at n=36A044421
- Numbers k such that string 8,9 occurs in the base 10 representation of k but not of k+1.at n=36A044802
- Sum of first n palindromic primes A002385.at n=15A046485
- Coordination sequence T1 for Zeolite Code AEN.at n=38A047950
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = n - 1 - 2^p and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = 1 and a(3) = 4.at n=12A049946
- Numbers k such that phi(k)*d(k) is a multiple of sigma(k), where d(k) is the number of divisors of k.at n=21A050934
- Discriminants of real quadratic number fields K with class number 2 such that the Hilbert class field of K is K(sqrt(17)).at n=38A052479