12465
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 21684
- Proper Divisor Sum (Aliquot Sum)
- 9219
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6624
- Möbius Function
- 0
- Radical
- 4155
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 63
- 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
- no
- Odd
- yes
Appears in sequences
- Expansion of (1+x)/cos(x).at n=9A009002
- Expansion of log(1 + tanh(x))/cos(x).at n=9A009391
- Expansion of e.g.f.: log(1+tanh(x))/cosh(x).at n=9A009392
- Expansion of e.g.f. x/cos(x) (odd powers only).at n=4A009843
- a(n) = Sum_{k=0..floor(n/2)-1} T(n,k) * T(n,k+2), with T given by A026009.at n=7A027289
- Consider all integer triples (i,j,k), j >= k > 0, with binomial(i+2,3)=j^3+k^3, ordered by increasing i; sequence gives j values.at n=13A054206
- Ninth column (k=8) of sextinomial array A063260.at n=7A063263
- Expansion of e.g.f. x * (tan(x) + sec(x)).at n=8A065619
- Triangle read by rows: T(n, k) = (-2)^k*binomial(n, k)*Euler(k, 1/2).at n=53A081658
- Number of consecutive prime runs of 1 prime congruent to 1 mod 4 below 10^n.at n=5A092636
- Numbers n occurring in binary representation of n*(n+1)/2.at n=42A092734
- Euler-Seidel matrix T(k,n) with start sequence e.g.f. 2x/(1+e^(2x)), read by antidiagonals.at n=45A099028
- Euler-Seidel matrix T(k,n) with start sequence e.g.f. 2x/(1+e^(2x)), read by antidiagonals.at n=46A099028
- Numbers k such that 7*10^k + 6*R_k + 3 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=24A103065
- Triangle, read by rows, equal to the matrix inverse of triangle A103327, where A103327(n,k) = binomial(2*n+1,2*k+1).at n=10A104033
- Triangle read by rows: T(n,k) is the number of alternating permutations on [n+1] with 1 in position k+1, 0<=k<=n.at n=53A104345
- Triangle read by rows: T(n,k) is the number of alternating permutations on [n+1] with 1 in position k+1, 0<=k<=n.at n=46A104345
- Triangle read by rows: T(n,k) is the number of alternating max-precedes-min permutations on [n+2] with 1 in position k+2, 0<=k<=n.at n=46A104346
- Triangle read by rows, T(n,k) = binomial(n,k)*A000111(n-k), 0 <= k <= n.at n=46A109449
- Exponential Riordan array (sech(x),x).at n=46A119879