5681
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
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6720
- Proper Divisor Sum (Aliquot Sum)
- 1039
- 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
- 4752
- Möbius Function
- -1
- Radical
- 5681
- Omega Function (Ω)
- 3
- 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
- 80
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- If a, b in sequence, so is ab+7.at n=39A009312
- Expansion of Product_{m>=1} (1+q^m)^(-13).at n=6A022608
- Numbers each of whose runs of digits in base 12 has length 2.at n=37A033010
- Number of partitions satisfying cn(0,5) = cn(2,5) + cn(3,5).at n=43A039859
- a(n) = Sum_{m=1..n, k=1..m} T(m,k), array T as in A049834.at n=34A049836
- Truncated triangular pyramid numbers: a(n) = (n-7)*(n^2 + 10*n - 108)/6, n >= 8.at n=25A051941
- Expansion of (1 + 4*x + 14*x^2 + 34*x^3 + 63*x^4 + 80*x^5 + 87*x^6 + 68*x^7 + 42*x^8 + 20*x^9 + 7*x^10) / ((1 - x)*(1 - x^2)^2*(1 - x^3)^2*(1 - x^4)).at n=10A055384
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 79 ).at n=22A063352
- Numbers m that divide binomial(m*(m+1), m+1)/m^2.at n=36A082529
- A sequence with a(n)/a(n-1) converging to 7, generated from a semi-magic square.at n=4A094944
- Numbers k such that 4*10^k+3 is prime.at n=14A101397
- Largest number that is not the sum of five n-gonal numbers.at n=18A118367
- Start with 34 and repeatedly reverse the digits and add 16 to get the next term.at n=43A119454
- Partial sums of floor(n^2/8).at n=51A122046
- Maximal number of squares of side 1 in a disk of radius n.at n=42A125228
- Number of partitions of n into parts which are not digits of n in decimal representation.at n=39A136460
- Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height 4.at n=20A152942
- Products of three consecutive happy primes A035497.at n=1A154716
- Products of three distinct happy primes A035497.at n=6A154717
- Numbers n with property that 42*n+37 is in A175284.at n=8A175285