6644
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 12768
- Proper Divisor Sum (Aliquot Sum)
- 6124
- 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
- 3000
- Möbius Function
- 0
- Radical
- 3322
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 3
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
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- Expansion of {Product_{j>=1} (1 - (-x)^j) - 1}^12 in powers of x.at n=9A001490
- Floor[n(n-1)(n-2)(n-3)/14].at n=19A011924
- Expansion of (1/theta_4 - 1)/2.at n=22A014968
- a(n) = n*(2*n^2 - 3*n + 4)/3.at n=22A037235
- a(n) = A033001(n)/4.at n=31A043307
- Numbers whose base-9 representation has exactly 5 runs.at n=1A043634
- Numbers k such that k | sigma_5(k).at n=36A055709
- Digits composite, each digit minus 1 is prime, sum of digits minus 1 is prime, difference of digits (in absolute value) minus 1 is prime.at n=29A058229
- a(n) = n*(n - 1)*(2*n^2 + n + 2)/6.at n=12A071246
- Triangle of T(n,k) where T(n,k)/(n-1)! is probability of player k out of n players winning a game of "Elimination": rules are that player 1 chooses one of the others at random to be eliminated, then player 2 (or 3 if player 2 has been eliminated) chooses somebody else at random from the survivors to be eliminated next, then the next surviving player chooses and so on round the circle until all but one have been eliminated.at n=42A071818
- a(n) = sum of the first n upper twin primes.at n=27A086168
- a(n) = Sum_{d|n} (n/d)^(d-1).at n=26A087909
- Number of n-digit base-2 deletable digit-sum multiple (DSM) integers.at n=17A101216
- {a(3,n)}, where a(m,n) is as defined in sequence A110576.at n=7A110579
- 4-almost primes with semiprime digits (digits 4, 6, 9 only).at n=12A111496
- Numbers k such that both k and the k-th prime have nonincreasing digits.at n=33A116067
- Number of partitions of n into parts with at most one 1 and at most one 2.at n=40A121081
- Expansion of q / (chi(-q) * chi(-q^3) * chi(-q^5) * chi(-q^15)) in powers of q where chi() is a Ramanujan theta function.at n=37A123632
- Indices of squares (of primes) in the semiprimes.at n=37A128301
- a(n) = 3*A146085(n) - 1.at n=30A146087