4944
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 20
- Divisor Sum
- 12896
- Proper Divisor Sum (Aliquot Sum)
- 7952
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1632
- Möbius Function
- 0
- Radical
- 618
- Omega Function (Ω)
- 6
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 28
- 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
- a(1) = 1; thereafter a(n+1) = floor(sqrt(2*a(n)*(a(n)+1))).at n=23A001521
- a(n) = Sum_{k=0..5} binomial(n,k).at n=15A006261
- Bond percolation series for mean cluster size on directed cubic lattice.at n=8A006810
- (d(n)-r(n))/5, where d = A006527 and r is the periodic sequence with fundamental period (4,1,4,0,1).at n=40A026036
- 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 11.at n=41A031509
- a(n) = 2^n - C(n,0)- ... - C(n,9).at n=15A035042
- Number of partitions of n with equal number of parts congruent to each of 2, 3 and 4 (mod 5).at n=49A035581
- Numbers having three 4's in base 10.at n=30A043507
- a(n) contains n digits (either '4' or '9') and is divisible by 2^n.at n=3A053333
- Numbers k such that phi(x) = k has exactly 12 solutions.at n=17A060675
- Integers n > 879 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 879.at n=24A063052
- a(n) = Sum_{k=0..n} binomial(3*n,k).at n=5A066380
- a(n) = Sum_{k=0..n} C(n*(n+1)/2,k).at n=5A066383
- Numbers that define integer Heronian triangles [prime(a(n)), prime(a(n)+1), A068965(n)] with area A068966(n).at n=13A068964
- Number of compositions of n into twin primes (i.e., primes that are members of a twin prime pair, like 3, 5, 7, 11, 13, but not 2 or 23).at n=39A077608
- a(1) = 1; a(n) = n multiplied by the concatenation of all previous terms.at n=3A095229
- Reversal of the binomial transform of the Whitney triangle A004070 (see A131250), triangle read by rows, T(n,k) for 0 <= k <= n.at n=60A097750
- a(n) = 100*n + 44.at n=49A102438
- Least positive k such that k * [RSA-200]^n - 1 is prime, where RSA-200 is the 200 decimal digit RSA challenge number A391940(15).at n=31A108375
- Numbers n such that 2*prime(n) - prime(n+1) is a square.at n=34A110975