12845
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 17664
- Proper Divisor Sum (Aliquot Sum)
- 4819
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8784
- Möbius Function
- -1
- Radical
- 12845
- 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
- 125
- 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
- 4-dimensional analog of centered polygonal numbers.at n=13A006323
- a(n) = T(n,n-6), array T as in A055801.at n=28A055806
- Triangle read by rows: T(n,m) = number of m-block proper T_0-covers (without empty blocks and without multiple blocks) of a labeled n-set (n>=2, 2<=m<=2^n-2).at n=21A095422
- 3-almost primes that are the sum of 2 positive cubes. Sums of 2 positive cubes, with the sums having exactly 3 prime divisors counted with multiplicity.at n=40A122732
- a(n) = 338*n + 1.at n=37A158000
- a(n) = 676*n + 1.at n=18A158386
- a(n) = 76*n^2 + 1.at n=13A158767
- Numbers k whose decimal expansion can be split into at least two parts whose binary equivalents can be concatenated (in the same order) to form the binary expansion of the original number k.at n=25A237041
- 30-gonal pyramidal numbers: a(n) = n*(n+1)*(28*n-25)/6.at n=14A256650
- Positive integers whose square is the sum of 50 consecutive squares.at n=13A257781
- a(1) = 6; for n > 1, a(n) = the least squarefree composite number whose sum of prime factors is prime and whose greatest prime factor is the sum of prime factors of a(n-1).at n=42A262081
- Numbers n such that 3*4^n - 1 is prime.at n=21A272057
- Numbers k such that k![4] + 2 is prime, where k![4] = A007662(k) = quadruple factorial.at n=36A283553
- Number of irredundant sets in the n X n white bishop graph.at n=5A290712
- Sphenic numbers that are also the sum of three consecutive primes.at n=45A335969
- Integer part of the product of three consecutive primes divided by their sum.at n=43A376334
- Square array A(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where column k is the expansion of e.g.f. B(x)^k, where B(x) is the e.g.f. of A140049.at n=49A379168