12915
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
- 24
- Divisor Sum
- 26208
- Proper Divisor Sum (Aliquot Sum)
- 13293
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 5760
- Möbius Function
- 0
- Radical
- 4305
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 169
- 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
- Number of 4-level labeled rooted trees with n leaves.at n=6A000307
- Odd abundant numbers (odd numbers m whose sum of divisors exceeds 2m).at n=28A005231
- Odd primitive abundant numbers.at n=20A006038
- a(n) = T(n,n-3), where T is the array in A026374.at n=27A026382
- Triangle read by rows: matrix 4th power of the Stirling2 triangle A008277.at n=15A039812
- Frobenius number of the numerical semigroup generated by three consecutive pentagonal numbers.at n=9A069757
- Odd primitive numbers such that n! divided by product of factorials of all proper divisors of n is not an integer.at n=16A075460
- Numbers k such that 3*k! + 1 is prime.at n=21A076679
- G.f.: A(x) = 1 + x*A(x)^2/(1-x-x^2).at n=8A084782
- G.f.: (1+x^3+x^4+x^5+x^6+x^9)/((1-x)*(1-x^2)^2*(1-x^3)*(1-x^4)).at n=38A090491
- If p(x) is the x-th prime, then the n-th set of 4 consecutive sexy prime pairs starts at p(a(n)).at n=20A095963
- Array T(n,k) = A153277(n-1,k) = A144150(n,k-1) read by downwards antidiagonals.at n=41A111672
- Number of partitions of 1 into fractions i/j with 1<=i<j<=n and i,j coprime.at n=18A115855
- Numbers n for which nontrivial positive magic squares of exactly 10 different orders with magic sum n exist. For a definition of nontrivial positive magic squares, see A125005.at n=30A125017
- Numbers k such that 19^k - 2 is a prime.at n=13A128460
- Binomial transform of [1, 5, 10, 10, 5, 1, 1, -1, 1, -1, 1, ...].at n=14A140228
- Square array A(n,k), n >= 0, k >= 0, read by antidiagonals, where the e.g.f. of column k is 1+g^(k+1)(x) with g = x-> exp(x)-1.at n=51A144150
- Array read by antidiagonals of higher order Bell numbers.at n=33A153277
- Odd almost practical numbers.at n=24A174535
- Odd abundant numbers whose abundance is even.at n=27A174865