2090
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
- 4320
- Proper Divisor Sum (Aliquot Sum)
- 2230
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 720
- Möbius Function
- 1
- Radical
- 2090
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 32
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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(1) = a(2) = 1, a(3) = 4; thereafter a(n) = a(n-1) + a(n-3).at n=19A001609
- a(n) = floor(Fibonacci(n)/2).at n=19A004695
- a(n) = floor(n*phi^10), where phi is the golden ratio, A001622.at n=17A004925
- Primitive pseudoperfect numbers.at n=34A006036
- Primitive nondeficient numbers.at n=28A006039
- Dodecahedral surface numbers: a(0)=0, a(1)=1, a(2)=20, thereafter 2*((3*n-7)^2 + 21).at n=13A007589
- Coordination sequence T2 for Zeolite Code ATS.at n=33A008039
- Coordination sequence T6 for Zeolite Code MFI.at n=29A008169
- Coordination sequence T4 for Zeolite Code MTW.at n=30A008199
- Coordination sequence T4 for Zeolite Code ZON.at n=32A009922
- Number of 5's in all the partitions of n into distinct parts.at n=53A015740
- Number of partitions of n into distinct parts, none being 5.at n=49A015750
- Numbers n such that phi(n) | sigma_7(n).at n=49A015765
- Numbers k such that phi(k) | sigma_13(k).at n=41A015771
- Expansion of 1/((1-3*x)*(1-5*x)*(1-9*x)).at n=3A017897
- Powers of fourth root of 5 rounded to nearest integer.at n=19A018058
- Powers of fourth root of 5 rounded up.at n=19A018059
- Balanced numbers: numbers k such that phi(k) (A000010) divides sigma(k) (A000203).at n=39A020492
- Numbers k such that d(k) (number of divisors) divides phi(k) (Euler function) divides sigma(k) (sum of divisors).at n=30A020493
- Convolution of (1, p(1), p(2), ...) and (F(2), F(3), F(4), ...).at n=11A023628