13268
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 24192
- Proper Divisor Sum (Aliquot Sum)
- 10924
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6360
- Möbius Function
- 0
- Radical
- 6634
- Omega Function (Ω)
- 4
- 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
- 94
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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) = integer nearest a(n-1)/(sqrt(7) - 2), where a(1) = 1.at n=21A024567
- a(n) = floor(floor(S3)/floor(S1)), where S3 and S1 are, respectively, the 3rd and first elementary symmetric functions of {sqrt(k), k = 1,2,...,n}.at n=54A025200
- Numbers k such that k^2 contains exactly 9 different digits.at n=11A054037
- a(1) = 1; set of digits of a(n)^2 is a subset of the set of digits of a(n+1)^2.at n=24A066825
- Unsigned row sums of triangle A152805.at n=9A152806
- Triangle read by rows: T(n,k) = Sum_{c in C(n,k)} lcm(c) where C(n,k) is the set of all k-subsets of {1,2,...,n}.at n=41A181853
- Numbers n such that n contains exactly 5 digits, all distinct, and n^2 contains exactly 9 distinct digits.at n=3A204691
- a(n) = Sum_{i=1...n} Sum_{j=1..i} lcm(i,j)/i.at n=46A232533
- Numbers n such that n^2048 + (n+1)^2048 is prime.at n=15A274235
- Indices of primes in A026007.at n=40A285223
- Number of Dyck paths of semilength n such that each level has exactly seven peaks or no peaks.at n=18A288114
- Number of partitions of n into parts that contain primes to odd powers only (A002035).at n=55A290369
- Number of nX3 0..1 arrays with every element equal to 1, 2, 3, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=6A299460
- Number of nX7 0..1 arrays with every element equal to 1, 2, 3, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=2A299464
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=38A299465
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 5, 6 or 8 king-move adjacent elements, with upper left element zero.at n=42A299465
- Number of nX7 0..1 arrays with every element equal to 1, 2, 3, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=2A300107
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=38A300108
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 3, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=42A300108
- a(n) = 2*n*(7*n - 3).at n=31A316466