4381
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 4732
- Proper Divisor Sum (Aliquot Sum)
- 351
- 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
- 4032
- Möbius Function
- 1
- Radical
- 4381
- 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
- 77
- 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
- no
- Odd
- yes
Appears in sequences
- G.f.: -1 + Product_{k>=1} (1 + prime(k)*x^prime(k)).at n=28A002099
- Numbers that are the sum of 9 positive 7th powers.at n=19A003376
- Stella octangula numbers: a(n) = n*(2*n^2 - 1).at n=13A007588
- Numbers k such that the geometric mean of phi(k) and sigma(k) is an integer.at n=45A011257
- Integers that are squarefree and also the sum of first k squarefrees for some k.at n=43A013932
- Apply partial sum operator thrice to Catalan numbers.at n=8A014151
- Geometric mean of phi(n) and sigma(n) is an integer, n odd.at n=17A015705
- Number of partitions of n into distinct parts, none being 2.at n=57A015744
- Number of projective order types.at n=9A018242
- Pseudoprimes to base 72.at n=20A020200
- Strong pseudoprimes to base 72.at n=8A020298
- a(n) = n*(13*n - 1)/2.at n=26A022270
- Convolution of natural numbers >= 2 and natural numbers >= 3.at n=25A023545
- a(n) = Sum_{k=0..floor(n/2)} A026615(n, k).at n=12A026623
- Sequence satisfies T^2(a)=a, where T is defined below.at n=51A027590
- "BGK" (reversible, element, unlabeled) transform of 1,1,1,1,...at n=25A032058
- Numbers k such that 221*2^k+1 is prime.at n=24A032487
- Numbers whose set of base-11 digits is {2,3}.at n=27A032811
- Numbers whose base-4 representation has exactly 7 runs.at n=7A043598
- Numbers k such that number of runs in the base 4 representation of k is congruent to 1 mod 6.at n=25A043838