8213
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8448
- Proper Divisor Sum (Aliquot Sum)
- 235
- 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
- 7980
- Möbius Function
- 1
- Radical
- 8213
- 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
- 39
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 72.at n=31A020411
- 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=23A029580
- a(n) = n * prime(n).at n=42A033286
- (s(n)+2)/10, where s(n)=n-th base 10 palindrome that starts with 8.at n=43A043087
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A048149.at n=24A049712
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 24.at n=35A051965
- Write 0,1,2,3,4,... in a triangular spiral; then a(n) is the sequence found by reading the terms along the line from 0 in the direction 0,2,...at n=43A062708
- Difference between average of smallest prime greater than n^3 and largest prime less than (n+1)^3 and n-th pronic [=n(n+1)].at n=18A063036
- Prefixing, suffixing or inserting a 9 in the number anywhere gives a prime.at n=34A069833
- a(n) = prime(n) * prime(prime(n)).at n=13A073065
- Product of upper bound twin-prime-indexed primes and their upper bound twin prime.at n=5A080701
- Leading diagonal of A083173.at n=42A083174
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=28A098936
- a(n) = 6*n^2 - 1.at n=37A140811
- Expansion of 1/(1 - x + x^2 - x^3 - x^6 + x^7 - x^8 + x^9 - x^10 + x^11 - x^12 -x^15 + x^16 - x^17 + x^18).at n=59A173911
- Number of 5-divided binary words of length n.at n=14A210322
- Number of partitions p of n such that the number of parts is a part and max(p) - min(p) is not a part.at n=44A241384
- Numbers n such that 8*n-1 is a triangular number.at n=45A274682
- a(n) = numerator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).at n=15A323779
- a(n) = numerator of Sum_{d|n} (tau(d)/sigma(d)) where tau(k) = the number of the divisors of k (A000005) and sigma(k) = the sum of the divisors of k (A000203).at n=47A323779