1640
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 3780
- Proper Divisor Sum (Aliquot Sum)
- 2140
- 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
- 640
- Möbius Function
- 0
- Radical
- 410
- Omega Function (Ω)
- 5
- 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
- yes
Recreational
- Happy Number
- no
- Harshad Number
- no
- 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
- no
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- a(n) = (3*n+1)*(3*n+2).at n=13A001504
- Oblong (or promic, pronic, or heteromecic) numbers: a(n) = n*(n+1).at n=40A002378
- Theta series of Borcherds' 27-dimensional unimodular lattice T_27.at n=3A002434
- a(n) = n*phi(n).at n=40A002618
- a(n) = 2*n*(2*n+1).at n=20A002943
- Number of partitions of n into Fibonacci parts (with a single type of 1).at n=41A003107
- Let S denote the palindromes in the language {0,1}*; a(n) = number of words of length n in the language SS.at n=13A007055
- a(n) = n OR n^2 (applied to binary expansions).at n=39A007745
- Coordination sequence T2 for Zeolite Code APC.at n=28A008033
- Coordination sequence T2 for Zeolite Code FER.at n=25A008107
- Coordination sequence T3 for Zeolite Code LOV.at n=27A008136
- Coordination sequence T1 for Zeolite Code MAZ.at n=28A008144
- Coordination sequence T1 for Zeolite Code MEP.at n=24A008157
- Coordination sequence T1 for Milarite.at n=25A008256
- Coordination sequence for D_5 lattice.at n=3A008355
- Expansion of (1+x^4)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=46A008765
- Expansion of (1+x^11)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=49A008772
- x -> x/2 if x even, x -> 3x - 1 if x odd.at n=19A008899
- a(n) = lcm(n, phi(n)).at n=40A009262
- Coordination sequence T2 for Zeolite Code RTH.at n=28A009894