12645
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
- 21996
- Proper Divisor Sum (Aliquot Sum)
- 9351
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6720
- Möbius Function
- 0
- Radical
- 4215
- 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
- 156
- 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
- a(n) = round(n*phi^14), where phi is the golden ratio, A001622.at n=15A004949
- a(n) = ceiling(n*phi^14), where phi is the golden ratio, A001622.at n=15A004969
- Number of labeled series-reduced dyslexic planted planar trees (root unlabeled) with n leaves.at n=5A032119
- E.g.f. x*(c(x/2)-1)/(1-2*x), where c(x) = g.f. for Catalan numbers A000108.at n=5A035101
- The convolution matrix of the double factorial of odd numbers (A001147).at n=16A035342
- a(n) = a(1) + a(2) + ... + a(n-1) + a(m) for n >= 4, where m = 2*n - 3 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 4.at n=13A049976
- a(n) is the (n+1)st (n+2)-gonal number.at n=29A064808
- Triangle of coefficients of even modified recursive orthogonal Hermite polynomials given in Hochstadt's book:P(x, n) = x*P(x, n - 1) - n*P(x, n - 2) ;A137286; P2(x,n)=P(x,n)+P(x,2*n): second type.at n=27A136587
- Triangle of coefficients of a version of the Hermite polynomials defined by P(x, n) = x*P(x, n - 1) - n*P(x, n - 2).at n=57A137286
- a(n) = 100*n^2 - 151*n + 57.at n=11A157626
- Number of binary strings of length n with equal numbers of 000 and 010 substrings.at n=16A164138
- The number of walks from (0,0,0,0) to (n,n,n,n) with steps that increment one to four coordinates and having the property that no two consecutive steps are orthogonal.at n=3A171563
- Coefficient triangle of the denominators of the (n-th convergents to) the continued fraction 1/(w+2/(w+3/(w+4/... . Conjectured to equal unsigned version of A137286.at n=57A180048
- G.f.: exp( Sum_{n>=1} A055457(n) * 5^A055457(n) * x^n/n ) where 5^A055457(n) exactly divides 5*n.at n=14A195761
- Number of edges in the Hasse diagram of the poset of conjugacy classes of subgroups of the alternating group.at n=12A218926
- Triangle read by rows: T(n,k) = T(n-1,k-1) + n*T(n-2,k); T(0,0) = T(1,0) = T(1,1) = 1, T(n,k) = 0 if k>n or if k<0.at n=57A230698
- Number of 5 X n binary arrays with rows and columns lexicographically nondecreasing and column sums nonincreasing.at n=7A266472
- a(n) = n * Sum_{k prime<=n} k.at n=44A301707
- Regular triangle read rows: T(n,k) = number of non-isomorphic multiset partitions of size n and length k.at n=57A317533
- Sum of the next n nonnegative integers repeated (A004526).at n=36A319007