8211
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 13824
- Proper Divisor Sum (Aliquot Sum)
- 5613
- 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
- 4224
- Möbius Function
- 1
- Radical
- 8211
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 158
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Triangular numbers written backwards.at n=47A004158
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly nine 1's.at n=28A020445
- Numbers whose sum of divisors is a cube.at n=43A020477
- a(n) = n*(31*n + 1)/2.at n=23A022289
- 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=22A029580
- a(n) = a(n-1)+ a(round(2*(n-1)/3)) +a(round((n-1)/3)) starting a(1)=1.at n=29A033498
- a(1)=10; if n = Product p_i^e_i, n > 1, then a(n) = Product p_{i+1}^e_i * Product p_{i+3}^e_i.at n=25A045973
- a(1) = 8; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=40A046258
- Geometric mean of the digits = 2. In other words, the product of the digits is = 2^k where k is the number of digits.at n=44A061426
- Numbers, not composed of the same digits, such that the geometric and arithmetic means of their decimal digits are integers.at n=33A067452
- Odd numbers k such that the number of 1's in binary representation of k equals omega(k), the number of distinct primes in the factorization of k.at n=17A071595
- Numbers k such that the product of the digits of k equals the number of divisors of k.at n=44A074312
- Number of polyhexes with n cells that tile the plane by 180-degree rotation (Conway criterion) but not by translation.at n=9A075210
- Subdiagonal of array of n-gonal numbers A081422.at n=20A081423
- Enumeration of partial sums of 1 + [1,2] + [2,3] + [1,2] + [2,3] + ...at n=27A089640
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=27A098936
- a(n) = ((9*n^2 + 33*n + 26)*2^n + (-1)^n)/27.at n=8A102841
- A106486-encodings of combinatorial games equivalent to game {0|0}.at n=18A125994
- Odd positive integers a(n) such that for every odd integer m>=7 there exists a unique representation of the form m=a(p)+2a(q)+4a(r).at n=19A147845
- Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height 5.at n=19A152943