3818
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
- 8
- Divisor Sum
- 6048
- Proper Divisor Sum (Aliquot Sum)
- 2230
- 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
- 1804
- Möbius Function
- -1
- Radical
- 3818
- 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
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 38
- 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 T5 for Zeolite Code MTT.at n=38A008193
- Coordination sequence T2 for Zeolite Code CZP.at n=40A019457
- a(n) = least 2k such that p is the least prime in a Goldbach partition of 2k, where p = prime(n).at n=21A025017
- Number of partitions of n into an even number of parts, the least being 4; also, a(n+4) = number of partitions of n into an odd number of parts, each >=4.at n=60A027196
- Numbers whose base-3 representation Sum_{i=0..m} d(i)*3^i has d(m) < d(m-1) > d(m-2) < ...at n=40A032841
- Dirichlet convolution of triangular numbers with themselves.at n=45A034715
- Numbers whose base-4 representation contains exactly four 2's and two 3's.at n=13A045155
- Number of partitions of n with equal nonzero number of parts congruent to each of 0, 1, 3 and 4 (mod 5).at n=63A046785
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the smallest integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = a(2) = a(3) = 1.at n=35A050024
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 1.at n=35A050040
- a(n) = a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 1.at n=35A050056
- Truncated square pyramid numbers: a(n) = Sum_{k = n..2*n-1} k^2.at n=12A050410
- 17-gonal (or heptadecagonal) numbers: a(n) = n*(15*n-13)/2.at n=23A051869
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 16.at n=35A051981
- Number of 4-element ordered antichains on an unlabeled n-element set; T_1-hypergraphs with 4 labeled nodes and n hyperedges.at n=2A056069
- a(n) = (s(n)-(n mod 2)) / n where s(n) is A006533.at n=46A056891
- Unitary untouchable numbers: us(x) = n has no solution where us(x) (A063919) is the sum of the proper unitary divisors of x.at n=26A063948
- Values of k for which A065358(k) is 0.at n=37A064940
- Sum( S(n,k) * M(k-1), k=1..n), where S(n,k) = Stirling numbers of the second kind, M(n) = Motzkin numbers, A001006.at n=7A069657
- Numbers n such that [A070080(n), A070081(n), A070082(n)] is an isosceles integer triangle with integer area.at n=14A070145