12649
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15680
- Proper Divisor Sum (Aliquot Sum)
- 3031
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9936
- Möbius Function
- -1
- Radical
- 12649
- 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
- 63
- 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
- Boustrophedon transform of partition numbers.at n=8A000751
- a(n) = 5*a(n-1) - a(n-2) for n > 1, a(0) = 0, a(1) = 1.at n=7A004254
- Pseudoprimes to base 96.at n=37A020224
- a(0)=2; a(n) is the smallest k > a(n-1) such that the fractional part of k^(1/11) starts with n.at n=36A034076
- Growth function of an infinite cubic graph (number of nodes at distance <=n from fixed node).at n=30A038621
- Denominators of continued fraction convergents to sqrt(21).at n=13A041033
- a(n) = binomial(n+5,4) - 1.at n=20A063258
- One-sixth the area of the smallest primitive d-arithmetic triangle, where d=A072330(n).at n=25A072360
- Table by antidiagonals of T(n,k)=n*T(n,k-1)-T(n,k-2) starting with T(n,1)=1.at n=59A073134
- Numerator of sum of reciprocals of first n 5-simplex numbers A000389.at n=20A118431
- Triangle read by rows: T(0,0)=1; for n >= 1 T(n,k) is the coefficient of x^k in the monic characteristic polynomial of the tridiagonal n X n matrix with main diagonal 5,5,5,... and sub- and superdiagonals 1,1,1,... (0 <= k <= n).at n=21A123967
- Fifth in an infinite set of generalized Pascal's triangles, with trigonometric properties.at n=34A125078
- Largest k > 1 such that (sum of digits of k^n)*(sum of digits of k^(n+1)) = k, or 0 if no such k exists.at n=5A130181
- E.g.f. satisfies: A(x) = x*(cosh(exp(A(x))-1)).at n=7A133359
- Denominators in continued fraction [0; 1, 3, 1, 3, 1, 3, ...].at n=12A136211
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, 1), (0, 1, 1), (1, 0, -1), (1, 1, 1)}.at n=7A150839
- If p and q are (odd) twin primes and q > p then p*q^2 + (p + q) + 1 is divisible by 6; a(n) = (p*q^2 + (p + q) + 1)/6.at n=5A151990
- Products of three distinct happy primes A035497.at n=14A154717
- Products of three distinct primes of the form 6*k + 1.at n=25A154729
- Triangle T(n, k, m) = t(n, m)/(t(k, m)*t(n-k, m)), where t(n, k) = Product_{j=1..n} p(j, k+1), p(n, x) = Sum_{j=0..n} (-1)^j*A053122(n, j)*x^j, and m = 6, read by rows.at n=29A156600