1318
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1980
- Proper Divisor Sum (Aliquot Sum)
- 662
- 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
- 658
- Möbius Function
- 1
- Radical
- 1318
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 52
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n+1) = 1 + a( floor(n/1) ) + a( floor(n/2) ) + ... + a( floor(n/n) ).at n=23A003318
- a(n) = least integer m > a(n-1) such that m - a(n-1) != a(j) - a(k) for all j, k less than n; a(1) = 1, a(2) = 2.at n=35A004978
- Rectilinear crossing number of complete graph on n nodes.at n=18A014540
- Numbers k such that phi(k) + 4 | sigma(k + 4).at n=49A015783
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite MEL = ZSM-11 Nan[AlnSi96-nO192] starting with a T7 atom.at n=10A019151
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite SGT = Sigma-2 [Si64O128].4R starting with a T2 atom.at n=10A019237
- Numbers k such that the continued fraction for sqrt(k) has period 50.at n=1A020389
- a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is an integer, s(0) = 0 = s(n), |s(i) - s(i-1)| = 1 for i = 1,2; |s(i) - s(i-1)| <= 1 for i >= 3. Also a(n) = T(n,n), where T is the array defined in A024996.at n=6A024997
- Numbers k such that A030787(k)=4.at n=47A030796
- 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 36.at n=1A031534
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 20 ones.at n=8A031788
- Concatenation of n and n + 5 or {n,n+5}.at n=12A032610
- Fractional part of square root of a(n) starts with 3: first term of runs.at n=33A034109
- Multiplicity of highest weight (or singular) vectors associated with character chi_13 of Monster module.at n=34A034401
- Number of 6-ary rooted trees with n nodes and height exactly 6.at n=12A036644
- Number of partitions satisfying (cn(0,5) = 0 and cn(2,5) = cn(3,5)).at n=36A036815
- Number of partitions of n such that cn(1,5) <= cn(0,5) = cn(2,5) < cn(3,5) = cn(4,5).at n=63A036852
- Even composite numbers whose digit sum equals the digit sum of (sum of prime factors, counted with multiplicity).at n=36A036922
- Numbers whose base-12 representation has the same nonzero number of 9's and 10's.at n=19A039556
- Numbers whose base-12 representation has the same nonzero number of 1's and 9's.at n=45A039611