1071
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 1872
- Proper Divisor Sum (Aliquot Sum)
- 801
- 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
- 576
- Möbius Function
- 0
- Radical
- 357
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 168
- 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
- no
- Odd
- yes
Appears in sequences
- Heptagonal numbers (or 7-gonal numbers): n*(5*n-3)/2.at n=21A000566
- Number of alkyls S C_{n+4} H_{2n+4} with n carbon atoms.at n=8A000650
- Absolute value of Glaisher's alpha(n).at n=12A002290
- Numbers k such that (k^2 + k + 1)/19 is prime.at n=32A002643
- Numbers that are the sum of 10 positive 5th powers.at n=43A003355
- Number of nonequivalent dissections of an n-gon into 3 polygons by nonintersecting diagonals rooted at a cell up to rotation and reflection.at n=17A003452
- Divisors of 2^24 - 1.at n=35A003532
- Divisors of 2^48 - 1.at n=43A003553
- Numbers that are a sum of distinct positive cubes in more than one way.at n=43A003998
- Numerators of approximations to e.at n=17A006258
- Number of sensed 2-connected simple planar maps with n edges.at n=8A006406
- Number of rooted toroidal maps with 4 vertices and n faces and no isthmuses.at n=1A006427
- Number of rooted toroidal maps with 2 faces, n vertices and no isthmuses.at n=3A006469
- Numbers k such that phi(k) = phi(sigma(k)).at n=40A006872
- a(0) = a(1) = 0; for n >= 2, a(n)*2^(n+2) + 1 is the smallest prime factor of the n-th Fermat number F(n) = 2^(2^n) + 1.at n=6A007117
- Coordination sequence T2 for Zeolite Code MOR.at n=21A008183
- Multiples of 21.at n=51A008603
- Expansion of 1/((1-x)*(1-x^3)*(1-x^5)*(1-x^7)*(1-x^9)).at n=58A008674
- Expansion of (1+x^10)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=42A008771
- Coordination sequence T2 for Zeolite Code DFO.at n=25A009876