9959
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10416
- Proper Divisor Sum (Aliquot Sum)
- 457
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9504
- Möbius Function
- 1
- Radical
- 9959
- 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
- 73
- Smith Number
- no
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = a(n-1) + a(n-2) with a(0)=2, a(1)=5. Sometimes called the Evangelist Sequence.at n=17A001060
- Numbers k such that 4*3^k - 1 is prime.at n=18A005540
- a(n) = F(n+1) + L(n), where F(n) and L(n) are Fibonacci and Lucas numbers, respectively.at n=18A013655
- Numbers such that ten iterations of Reverse and Add are needed to reach a palindrome.at n=12A015991
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 99.at n=13A031597
- Numerators of continued fraction convergents to sqrt(787).at n=5A042516
- Numbers having three 9's in base 10.at n=23A043527
- a(n)=Sum{T(n,j): j=1,2,...,n}, array T given by A048201.at n=23A048209
- Sum of digits = 8 times number of digits.at n=44A061425
- Numbers which need ten 'Reverse and Add' steps to reach a palindrome.at n=11A065215
- One half of the number of non-self-conjugate balanced partitions.at n=54A067772
- Second convolution of A001045(n+1) (generalized (1,2)-Fibonacci), n>=0, with itself.at n=9A073372
- Numbers k such that k^4 = x^3 + y^2 has an integer solution.at n=33A096741
- Near-repdigit semiprimes with 9 as repeated digit.at n=20A105990
- Numbers k such that 2*k+1, 3*k+2 and 4*k+3 are primes.at n=42A126955
- a(n) = pq + pr + qr with p = prime(n), q = prime(n+1), and r = prime(n+2).at n=15A127345
- Composites in A127345.at n=6A127347
- Numbers k such that k and k^2 use only the digits 1, 5, 6, 8 and 9.at n=6A137062
- G.f.: limit of the ratio of the g.f.s of adjacent rows in triangle A152800.at n=32A152803
- a(1)=2, a(2)=3, then a(n)=a(n-1)+a(n-2) if n odd, a(n)=a(n-1)-a(n-2) if n even.at n=34A174562