13827
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 20160
- Proper Divisor Sum (Aliquot Sum)
- 6333
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8360
- Möbius Function
- -1
- Radical
- 13827
- 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
- 45
- 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 n such that phi(n + phi(n)) = sigma(n).at n=18A074874
- a(n) = running sum of the first n harmonic numbers, multiplied by the LCM of 1..n.at n=7A081530
- Duplicate of A081530.at n=7A081886
- a(n) = n^3 + 3.at n=24A084378
- Number of permutations of length n which avoid the patterns 1234, 1243, 1432.at n=8A116772
- Triangle read by rows: T(n,k) = the number of Dyck paths of semilength n with k UDDU's.at n=31A135306
- Number of Dyck paths of semilength n that do not contain the string UDDU.at n=11A135307
- Numbers that are the product of 3 distinct primes a,b and c, such that a+b+c, a^2+b^2+c^2 and a^3+b^3+c^3 are prime numbers.at n=18A176911
- Number of ordered triples (w,x,y) with all terms in {1,...,n} and 2w^3<=x^3+y^3.at n=28A211807
- Irregular triangle read by rows: T(n,k) = number of meanders with n bridges in which the first bridge is bridge k.at n=68A259974
- Triangle read by rows: T(n,k) is the number of unlabeled simple series-reduced 2-connected graphs with n nodes and k edges (n >= 4, ceiling(3*n/2) <= k <= n*(n-1)/2).at n=46A339069
- Number of multiset partitions of integer partitions of n such that all blocks have odd size.at n=18A356932
- Number of edges in an equilateral triangle when n internal equilateral triangles are drawn between the 3n points that divide each side into n+1 equal parts.at n=48A357008