8203
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8848
- Proper Divisor Sum (Aliquot Sum)
- 645
- 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
- 7560
- Möbius Function
- 1
- Radical
- 8203
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 158
- 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+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=18A029580
- Number of partitions satisfying cn(0,5) < cn(1,5) + cn(4,5) + cn(2,5) + cn(3,5).at n=31A039848
- (s(n)+2)/10, where s(n)=n-th base 10 palindrome that starts with 8.at n=42A043087
- Numbers whose base-4 representation contains exactly four 0's and no 1's.at n=23A045033
- Numbers whose base-4 representation contains exactly four 0's and two 2's.at n=22A045059
- Numbers whose base-5 representation contains exactly two 0's and three 3's.at n=21A045198
- Semiprimes whose prime factors, when concatenated, yield a palindrome.at n=45A046451
- Number of positive integers <= 2^n of form 6 x^2 + 9 y^2.at n=17A054184
- Semiprimes p1*p2 such that p2>p1 and p2 mod p1 = 7.at n=40A064905
- a(n) is the smallest k such that number of non-unitary prime divisors of central binomial coefficient, A000984(k) = C(2*k,k) equals n.at n=20A081393
- a(n) = 2^(n+1) + n - 1.at n=12A083706
- Triangular matchstick numbers in the class of prime numbers: sum of n-th and next n primes.at n=33A105720
- Least positive k such that 2^n + k is a Chen prime and 2^n + k + 2 is a brilliant number.at n=31A109364
- a(1) = a(2) = 1, a(n) = A007947(a(n-1)) + a(n-2), for n >= 3, i.e., a(n) = a(n-2) plus the largest squarefree divisor of a(n-1).at n=24A121368
- Duplicate of A083706.at n=12A122039
- A106486-encodings of combinatorial games equivalent to game {0|0}.at n=17A125994
- a(n) = smallest multiple of n which is >= 2^n.at n=12A128093
- Semiprimes whose factors are decimal palindromes when concatenated, omitting multiples of primes less than 11.at n=22A144719
- Numbers k such that k, k + 1 and k + 2 are 3 consecutive Harshad numbers.at n=23A154701
- a(n) = Sum_{k=1..n} binomial(n,k) * gcd(k,n).at n=12A159068