13278
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
- 26568
- Proper Divisor Sum (Aliquot Sum)
- 13290
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 4424
- Möbius Function
- -1
- Radical
- 13278
- 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
- 76
- 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
- a(n) = Sum_{k=0..n} binomial(n,k^2).at n=16A003099
- Numbers k such that k^2 contains exactly 9 different digits.at n=12A054037
- Triangle read by rows: T(n,k) (n >= 2, 1<=k<=n-1) is the number of permutations p of 1,...,n with max(|p(i)-p(i-1)|, i=2..n) = k.at n=47A064482
- Number of 7/3+-power-free words over the alphabet {0,1}.at n=35A082380
- Number of (n+1)X(n+1) 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=4A186463
- Number of (n+1)X6 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=4A186468
- T(n,k)=Number of (n+1)X(k+1) 0..2 arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=40A186472
- T(n,m)=Number of (n+1)X6 0..m arrays with every 2X2 subblock commuting with each of its horizontal and vertical 2X2 subblock neighbors.at n=19A188837
- Numbers n such that n contains exactly 5 digits, all distinct, and n^2 contains exactly 9 distinct digits.at n=4A204691
- a(n) = Sum_{k=0..n} binomial(n^2, k^2).at n=4A206849
- a(n) = n*(7*n^2 - 3*n - 1)/3.at n=18A214659
- Expansion of f(-x, -x^5)^2 / f(x, x^3) in powers of x where f(, ) is Ramanujan's general theta function.at n=34A263041
- Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-2) + 2, where a(0) = 1, a(1) = 2, b(0) = 3.at n=16A294534
- First term of n-th difference sequence of (floor(k*r)), r = sqrt(2/3), k >= 0.at n=17A325731
- Numbers k such that any two consecutive decimal digits of k^2 differ by 1 after arranging the digits in decreasing order.at n=27A370362