15490
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 27900
- Proper Divisor Sum (Aliquot Sum)
- 12410
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6192
- Möbius Function
- -1
- Radical
- 15490
- 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
- 53
- 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
- yes
- Odd
- no
Appears in sequences
- Coordination sequence for body-centered tetragonal lattice.at n=44A008527
- a(0) = 1, a(n) = 32*n^2 + 2 for n > 0.at n=22A010021
- Numbers k such that 207*2^k + 1 is prime.at n=45A032480
- Number of partitions of n into parts not of the form 25k, 25k+5 or 25k-5. Also number of partitions with at most 4 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=37A036004
- Becomes prime or 4 after exactly 9 iterations of f(x) = sum of prime factors of x.at n=6A048131
- Numbers k such that (3^k - 7)/2 is prime.at n=14A063679
- Number of A095318-primes in range ]2^n,2^(n+1)].at n=18A095328
- Number of A095314-primes in range ]2^n,2^(n+1)].at n=18A095334
- a(n) = (2*n-1)^2 + (2*n+1)^2.at n=44A108100
- Half the number of 0..3 arrays of length n+2 with second differences nonzero.at n=5A212777
- T(n,k)=Half the number of 0..k arrays of length n+2 with second differences nonzero.at n=33A212782
- Half the number of 0..n arrays of length 8 with second differences nonzero.at n=2A212787
- a(n) = a(n-2) + 2*a(n-3) for n >= 3, where a(0) = 2, a(2) = 4, a(3) = 5.at n=21A288668
- Square array T(n,k), n>=0, k>=0, read by antidiagonals, where T(0,k) = 1 and T(n,k) = (1/n) * Sum_{j=1..n} binomial(n,j) * binomial(n+(k-1)*j,j-1) for n > 0.at n=61A336706
- G.f. A(x) satisfies A(x) = 1 + x*A(x)^4 / (1 - x*A(x)).at n=6A364747
- a(n) = index of n in A368382, or -1 if n is missing from that sequence.at n=34A368383