8209
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 8210
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 8208
- Möbius Function
- -1
- Radical
- 8209
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 39
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1029
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/4.at n=49A001134
- Restricted partitions.at n=18A002574
- Largest prime factor of 3^(2n+1) - 1.at n=13A002591
- Somos-4 sequence: a(0)=a(1)=a(2)=a(3)=1; for n >= 4, a(n) = (a(n-1) * a(n-3) + a(n-2)^2) / a(n-4).at n=11A006720
- Expansion of layer susceptibility series for cubic lattice.at n=6A007287
- Next prime after 2^n.at n=13A014210
- Primes that remain prime through 3 iterations of function f(x) = 9x + 2.at n=24A023296
- Expansion of 1/((1-4x)(1-6x)(1-8x)(1-11x)).at n=3A028137
- Numbers n such that n divides the (right) concatenation of all numbers <= n written in base 7 (most significant digit on right).at n=13A029500
- a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p diving [ A*a(n)+B ] and p=2, A=2.00013, B=3.0.at n=21A029580
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 76 ones.at n=0A031844
- Upper prime of a difference of 18 between consecutive primes.at n=34A031937
- Primes with first digit 8.at n=38A045714
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 4.at n=14A049913
- Odd numbers seen in decimal expansion of Pi (disregarding the decimal period) contiguous, smallest and distinct.at n=20A050817
- Primes followed by a [10,2,10] prime difference pattern of A001223.at n=13A052376
- Fifth term of weak prime quintets: p(m-3)-p(m-4) < p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1).at n=20A054827
- Primes p+2^n arising in A056206.at n=13A056208
- First member of a prime triple in a 2p-1 progression.at n=38A057326
- a(1) = 2; a(n+1) is obtained by writing a(n) in binary and trying to complement just one bit, starting with the least significant bit, until a new prime is reached.at n=10A059459