8864
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 26
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 17514
- Proper Divisor Sum (Aliquot Sum)
- 8650
- 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
- 4416
- Möbius Function
- 0
- Radical
- 554
- Omega Function (Ω)
- 6
- 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
- 21
- Smith Number
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- Numbers k where |cos(k)| (or |cosec(k)| or |cot(k)|) decreases monotonically to 0; also numbers k where |tan(k)| (or |sec(k)|, or |sin(k)|) increases.at n=30A004112
- a(1)=1, a(n) = 20*a(n-1) + n.at n=3A014904
- Expansion of (1/theta_4 - 1)/2.at n=23A014968
- a(n) = Sum_{i=1..floor((n+1)/4)} a(2*i-1) * a(n-2*i+1), with a(1)=a(3)=2 and a(2)=1.at n=12A024739
- Least k such that tan(k) > tan(a(n-1)), for n >= 1, where a(0) = 0.at n=41A024814
- 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 47.at n=19A031545
- Numbers whose set of base-14 digits is {2,3}.at n=28A032814
- Numbers whose base-4 representation contains exactly three 0's and four 2's.at n=9A045056
- Sin(n) decreases monotonically to -1.at n=17A046964
- Number of permutations of length n which avoid the patterns 1234 and 1324.at n=8A053617
- Number of primes between successive powers of e (= 2.718281828...).at n=11A061273
- Harmonic mean of digits is 6.at n=19A062184
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 85 ).at n=34A063358
- Numbers k such that floor(tan(k)) > floor(tan(m)) for all m < k.at n=38A063537
- a(0)=1; a(n) is the smallest integer > a(n-1) such that sin(a(n)) is closer to an integer (here 0 or -1) than sin(a(n-1)).at n=16A079037
- Indices of primes which remain prime if any one digit is deleted (leading zeros allowed).at n=42A084375
- Riordan array (1/(1-2*x), x*(1+x)/(1-2*x)).at n=47A121574
- Cubes (n * n * n) in carryless arithmetic mod 10.at n=24A169885
- a(1) = 1, and for each k >=2, a(k) is the smallest number n such that n/cos(n) > a(k)/cos(a(k)), so that a(1)/cos(a(1)) > a(2)/cos(a(2)) > ... > a(k)/cos(a(k)) > ...at n=27A172446
- a(1) = 1, and for each n >=2, a(n) is the smallest number such that 1/cos(a(n)) < 1/cos(k) for all k < n, so that 1/cos(a(1)) > 1/cos(a(2)) > ... > 1/cos(a(n)) > ...at n=16A172448