7941
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
- 4
- Divisor Sum
- 10592
- Proper Divisor Sum (Aliquot Sum)
- 2651
- 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
- 5292
- Möbius Function
- 1
- Radical
- 7941
- 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
- 52
- 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 78.at n=20A020417
- 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 58.at n=35A031556
- Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 3,2,1,0.at n=4A037796
- a(n) = Sum_{k=1..floor(n/2)} T(n, 2k), array T as in A049777.at n=34A049779
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 22.at n=32A051963
- G.f.: (1 + Sum_{ i >= 0 } 2^i*x^(2^(i+1)-1)) / (1-x)^3.at n=38A063916
- a(0)=1; for n > 0, a(n)=sum(binomial(n,k)*(binomial(n+k,k+1)^2)* binomial(n+k,k),k=0..n).at n=3A075514
- Numbers n such that the partition function A000041(k) is even and odd the same number of times for 0 <= k <= n.at n=3A098936
- a(n) = a(n-1)+a(n-2)-a(n-3)+a(n-5), n>7.at n=27A107287
- Sum of primes between n and n^2.at n=16A109818
- Numbers k such that k and 8*k, taken together, are zeroless pandigital.at n=25A115932
- Start with 1 and repeatedly reverse the digits and add 64 to get the next term.at n=29A118159
- Abs(*+-) n Sequence.at n=40A119518
- Expansion of c(2*x^2)/(1-x*c(2*x^2)), where c(x) = (1-sqrt(1-4*x))/(2*x) is the g.f. of the Catalan numbers (A000108).at n=11A126087
- Integer part of Gauss's Arithmetic-Geometric Mean M(2,n^5).at n=8A127766
- Row sums of triangle A144334, binomial transform of [1, 2, 6, 7, 3, 0, 0, 0, ...].at n=15A144335
- Number of n X n binary arrays with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.at n=5A145925
- Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.at n=13A145927
- a(n) = 361*n - 1.at n=21A158308
- a(n) = 22*n^2 - 1.at n=18A158540