1440
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
- 36
- Divisor Sum
- 4914
- Proper Divisor Sum (Aliquot Sum)
- 3474
- 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
- 384
- Möbius Function
- 0
- Radical
- 30
- Omega Function (Ω)
- 8
- 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
- 21
- 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
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- Partial sums of (unordered) ways of making change for n cents using coins of 1, 2, 5, 10 cents.at n=34A000064
- Number of cusps of principal congruence subgroup Gamma^{hat}(n).at n=53A000114
- Number of ways of writing n as a sum of 5 squares.at n=33A000132
- Jordan-Polya numbers: products of factorial numbers A000142.at n=34A001013
- Number of black-rooted red-black trees with n internal nodes.at n=12A001137
- Index of (the image of) the modular group Gamma(n) in PSL_2(Z).at n=14A001766
- Highly abundant numbers: numbers k such that sigma(k) > sigma(m) for all m < k.at n=47A002093
- High temperature series for spin-1/2 Heisenberg specific heat on 3-dimensional b.c.c. lattice.at n=4A002167
- a(n) = n! * lcm({1, 2, ..., n+1}).at n=4A002397
- Squares written in base 9.at n=32A002442
- Values of phi(k) when phi(k) = phi(k+1).at n=13A003275
- High temperature series for internal energy for spherical model on f.c.c. lattice.at n=4A003498
- a(1) = 1; for n>1, a(n) = a(n-1) + 1 + sum of distinct prime factors of a(n-1) that are < a(n-1).at n=44A003508
- Expansion of (1-x+x^2)/((1-x)^2*(1-x^2)*(1-x^4)).at n=38A005232
- Bishops on an n X n board (see Robinson paper for details).at n=11A005633
- Expansion of 6-dimensional cusp form (eta(q) * eta(q^3))^6 in powers of q.at n=32A007332
- Smallest k such that sigma(x) = k has exactly n solutions.at n=21A007368
- Jordan function J_2(n) (a generalization of phi(n)).at n=43A007434
- Frequency of n-th largest distance in N times N times N grid, N > n.at n=48A007544
- Dwork-Kontsevich sequence evaluated at 2*n.at n=4A007757