1620
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
- 30
- Divisor Sum
- 5082
- Proper Divisor Sum (Aliquot Sum)
- 3462
- 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
- 432
- Möbius Function
- 0
- Radical
- 30
- Omega Function (Ω)
- 7
- 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
- 29
- 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
- Highly abundant numbers: numbers k such that sigma(k) > sigma(m) for all m < k.at n=49A002093
- a(n) = n^2*(n^2 - 1)/4.at n=9A006011
- Numbers not of form p + 2^x + 2^y.at n=34A006286
- a(n) = n*(4*n+1).at n=20A007742
- Coordination sequence T8 for Zeolite Code EUO.at n=25A008103
- Coordination sequence T6 for Zeolite Code MTT.at n=25A008194
- Coordination sequence T1 for feldspar.at n=27A008254
- Theta series of A_5 lattice.at n=14A008445
- List of ordered areas of Pythagorean triangles.at n=50A009111
- Areas of Pythagorean triangles: numbers which can be the area of a right triangle with integer sides.at n=46A009112
- a(n) is (n+1)!*(n+2)! times coefficient of x^n in (log(1-x))^-1.at n=4A009763
- Coordination sequence T2 for Zeolite Code WEI.at n=29A009918
- Terms in perturbation solution of a heat transfer problem.at n=9A013704
- a(n) = Sum_{i,j,k in Z and i^2 + j^2 + k^2 <= n} i^2 + j^2 + k^2.at n=13A014203
- Numbers k such that s(j) < s(k) for all j < k, where s = A014405.at n=56A014407
- Theta series of lattice Kappa_9.at n=4A015233
- Expansion of 1/(1-x^10-x^11-x^12-x^13-x^14-x^15-x^16-x^17-x^18).at n=61A017894
- Number of lines through exactly 6 points of an n X n grid of points.at n=30A018813
- Coordination sequence T2 for Zeolite Code CZP.at n=26A019457
- Define the sequence T(a_0,a_1) by a_{n+2} is the greatest integer such that a_{n+2}/a_{n+1}<a_{n+1}/a_n for n >= 0. This is T(7,43).at n=3A022036