12946
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
- 4
- Divisor Sum
- 19422
- Proper Divisor Sum (Aliquot Sum)
- 6476
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6472
- Möbius Function
- 1
- Radical
- 12946
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 125
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; initial terms are 2,3,4.at n=15A049876
- Numbers k such that 3*2^k + 7 is prime.at n=30A059746
- a(n) = 7 + floor((2 + Sum_{j=1..n-1} a(j))/3).at n=26A120153
- Triangle read by rows, where t(n,1) = 1, t(n,m) = t(n,m-1) + (largest nonprime {1 or composite} in row {n-1}).at n=46A120853
- a(0)=0, a(1)=1; and a(n) = a(n-1) + a(a(n-1) mod n) for n>=2.at n=47A125204
- The sequence b[n] defined in A126940.at n=9A126946
- G.f. satisfies: A(x) = (1+x) * A(x^2)*A(x^3)*A(x^4)*...*A(x^n)*...at n=33A129373
- a(n) = 1681*n^2 - 756*n + 85.at n=2A157010
- Semiprimes that are the sum of 10 consecutive primes.at n=16A185347
- Number of 8-step one space for components leftwards or up, two space for components rightwards or down asymmetric quasi-bishop's tours (antidiagonal moves become knight moves) on an n X n board summed over all starting positions.at n=7A187612
- Numbers that are the sum of 10 consecutive primes and also the sum of 10 consecutive semiprimes.at n=1A284102
- Number of maximal irredundant sets in the n-gear graph.at n=9A290640
- Number of compositions of n where every distinct subsequence (not necessarily contiguous) has a different sum.at n=37A334268
- a(0) = 1; a(n) = 2 * Sum_{k=0..n-1} binomial(n,k)^2 * a(k).at n=4A336217
- Maximal coefficient of (1 + x^2) * (1 + x^2 + x^3) * (1 + x^2 + x^3 + x^5) * ... * (1 + x^2 + ... + x^prime(n)).at n=8A369775
- Irregular table read by rows: T(n,k) is the number of k-gons, k>=2, among all distinct circles that can be constructed from the 3 vertices and the equally spaced 3*n points placed on the sides of an equilateral triangle, using only a compass.at n=35A372617