1838
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2760
- Proper Divisor Sum (Aliquot Sum)
- 922
- 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
- 918
- Möbius Function
- 1
- Radical
- 1838
- 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
- 130
- 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
- Number of fixed 2-dimensional triangular-celled animals with n cells (n-iamonds, polyiamonds) in the 2-dimensional hexagonal lattice.at n=8A001420
- Numbers k such that phi(2k-1) < phi(2k), where phi is Euler's totient function A000010.at n=25A001836
- Coordination sequence T2 for Zeolite Code PHI.at n=31A008228
- Coordination sequence T2 for Zeolite Code -ROG.at n=32A009860
- Coordination sequence for MgCu2, Cu position.at n=11A009930
- Number of ordered triples of integers from [ 1,n ] with no common factors between pairs.at n=32A015632
- Numbers k such that the continued fraction for sqrt(k) has period 24.at n=25A020363
- a(n) = [ C(2n,n)/(n-1) ].at n=6A024499
- Functions on n points with a single labeled point.at n=7A027853
- a(n) = least k such that 1+2+...+k >= E{1,2,...,n}, where E is the 3rd elementary symmetric function.at n=18A027917
- Size of lexicographic code of length n, Hamming distance 8 and weight 8.at n=29A030069
- [ exp(15/16)*n! ].at n=5A030900
- 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 42.at n=6A031540
- Triangular array associated with Schroeder numbers.at n=40A033878
- Numbers k such that k-th and (k+1)-st term of A038593 differ by 9.at n=47A038640
- Numbers having two 8's in base 10.at n=38A043522
- Numbers k such that string 3,4 occurs in the base 7 representation of k but not of k-1.at n=42A044163
- Numbers n such that string 5,6 occurs in the base 8 representation of n but not of n-1.at n=31A044233
- Numbers k such that the string 6,2 occurs in the base 9 representation of k but not of k-1.at n=24A044307
- Numbers n such that string 3,8 occurs in the base 10 representation of n but not of n-1.at n=20A044370