6619
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 6620
- 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
- 6618
- Möbius Function
- -1
- Radical
- 6619
- 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
- 137
- 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
- 855
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Let A(n) = #{(i,j,k): i^2 + j^2 + k^2 <= n}, V(n) = (4/3)*Pi*n^(3/2), P(n) = A(n) - V(n); A000092 gives values of n where |P(n)| sets a new record; sequence gives A(A000092(n)).at n=11A000413
- Prime(n)*...*a(n) is the least product of consecutive primes which is non-deficient.at n=20A007686
- Prime(n)*...*a(n) is the least product of consecutive primes which is abundant.at n=20A007708
- 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 81.at n=5A031579
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 62 ones.at n=2A031830
- Lower prime of a difference of 18 between consecutive primes.at n=26A031936
- Discriminants of imaginary quadratic fields with class number 13 (negated).at n=23A046010
- Primes p such that pp'-2 is prime, where p' denotes the next prime after p.at n=38A048797
- Primes that yield a different prime when rotated by 180 degrees.at n=22A048890
- Primes of the form 4*k^2 + 4*k + 59.at n=35A048988
- Largest prime dividing Sum_{k=0..n} k! * (n-k)!.at n=20A049413
- First term of strong prime quintets: p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2) > p(m+4)-p(m+3).at n=17A054808
- Minimum solution for tri-color tower of Hanoi, restricted so like colors can't be together.at n=10A055622
- The primes in A045574.at n=42A057770
- A064434(n) = 0.at n=8A064456
- The first of two consecutive primes with equal digital sums.at n=18A066540
- Odd prime values of sigma(k) - phi(k) taking k in increasing order.at n=30A068419
- Number of partitions of n in which no part appears more than twice and no two parts differ by 1.at n=54A070047
- a(1)=1, a(n) is the smallest integer > a(n-1) such that the largest element in the simple continued fraction for S(n)=1/a(1)+1/a(2)+...+1/a(n) equals n^3.at n=6A070903
- Primes that are still primes when turned upsided down.at n=26A080788