9985
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 31
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11988
- Proper Divisor Sum (Aliquot Sum)
- 2003
- 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
- 7984
- Möbius Function
- 1
- Radical
- 9985
- 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
- 91
- 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
- no
- Odd
- yes
Appears in sequences
- MacMahon's solid partitions of n in which 4 is the smallest summand.at n=12A002045
- a(n) is the smallest positive number such that the sum of A001032(n) consecutive squares starting with a(n)^2 is a square.at n=44A007475
- Numbers k such that the continued fraction for sqrt(k) has period 61.at n=7A020400
- Sizes of successive balls in D_4 lattice.at n=31A046949
- Number of 4-element intersecting families (of distinct sets) whose union is an n-element set.at n=4A052391
- Number of hyperbolic knots with n crossings (A002863 - A051764 - A051765).at n=12A052408
- Numbers k such that k, k+2, k+4, k+6, k+8 are semiprimes.at n=30A092127
- Numbers k such that k, k+2, k+4, k+6, k+8, k+10 are semiprimes.at n=9A092128
- Numbers k such that k, k+2, k+4, k+6, k+8, k+10, k+12 are semiprimes.at n=4A092129
- Figurate numbers based on the 600-cell (4-D polytope with Schlaefli symbol {3,3,5}).at n=4A092182
- a(n) = A100092(n^2+n+1).at n=12A100094
- Composite numbers between largest n-digit prime and the smallest (n+1) digit prime.at n=28A109936
- a(n) = 10^n - 2^n + 1^n.at n=4A155601
- Positive numbers y such that y^2 is of the form x^2+(x+233)^2 with integer x.at n=8A157297
- a(n) = 256*n + 1.at n=38A158231
- Upper s-Wythoff sequence, where s=A081276 (eighth cubes). Complement of A184431.at n=41A184432
- 1000-gonal numbers: a(n) = n*(499*n - 498).at n=5A195163
- G.f. satisfies: A(x) = exp( Sum_{n>=1} x^n/n * Product_{k>=1} 1/(1 - x^(n*k)*A(x^k)^n) ).at n=10A218551
- Values of n such that L(10) and N(10) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.at n=37A227448
- a(n) = 384*n + 1.at n=26A229853