1780
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 3780
- Proper Divisor Sum (Aliquot Sum)
- 2000
- 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
- 704
- Möbius Function
- 0
- Radical
- 890
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 73
- 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
- yes
- Odd
- no
Appears in sequences
- Expansion of 1/((1-x)^2*(1-x^2)*(1-x^5)).at n=43A001304
- Number of semigroups of order n with 2 idempotents, considered to be equivalent when they are isomorphic or anti-isomorphic (by reversal of the operator).at n=4A002787
- Numbers that are the sum of 9 positive 6th powers.at n=24A003365
- a(n) = (2^n + C(2*n,n))/2.at n=7A005317
- Coordination sequence T4 for Zeolite Code AFR.at n=32A008022
- Coordination sequence T2 for Zeolite Code AST.at n=31A008037
- Coordination sequence T1 for Zeolite Code EUO.at n=26A008095
- Coordination sequence T7 for Zeolite Code EUO.at n=26A008102
- Coordination sequence T1 for Zeolite Code JBW.at n=28A008121
- Coordination sequence T2 for Zeolite Code LAU.at n=30A008125
- Coordination sequence T4 for Zeolite Code MFS.at n=26A008176
- 3x+1 sequence starting at 97.at n=45A008873
- 3x+1 sequence starting at 63.at n=34A008874
- 3x+1 sequence starting at 95.at n=32A008875
- 3x+1 sequence starting at 27.at n=38A008884
- Magic numbers: atoms with full shells containing any of these numbers of electrons are considered electronically stable.at n=19A018227
- Number of lines through exactly 9 points of an n X n grid of points.at n=53A018816
- a(n) = n^2 - phi(n)*tau(n)^2.at n=49A022157
- Fibonacci sequence beginning 0, 20.at n=11A022354
- a(n) = [ a(n-1)/a(1) + a(n-3)/a(3) + a(n-5)/a(5) + ... ], for n >= 3.at n=30A022871