2045
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
- 4
- Divisor Sum
- 2460
- Proper Divisor Sum (Aliquot Sum)
- 415
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1632
- Möbius Function
- 1
- Radical
- 2045
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 63
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Number of partially ordered sets ("posets") with n unlabeled elements.at n=7A000112
- Coordination sequence T2 for Zeolite Code MOR.at n=29A008183
- Coordination sequence T4 for Zeolite Code NES.at n=29A008208
- Coordination sequence T3 for Zeolite Code -PAR.at n=32A009857
- Coordination sequence T1 for Zeolite Code TER.at n=30A016433
- Base 6 expansion uses each positive digit just once.at n=6A023744
- Integer part of ((4th elementary symmetric function of 2,3,...,n+4)/(2nd elementary symmetric function of 2,3,...,n+4)).at n=14A024181
- Expansion of e.g.f. sinh(exp(x)-1).at n=8A024429
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (Lucas numbers), t = (composite numbers).at n=14A024471
- a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/2n} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k.at n=14A024848
- Number of partitions of n in which the least part is 7.at n=72A026800
- Number of prime unlabeled T_0 topologies (i.e., prime T_0 homeomorphism classes) on n points.at n=5A028856
- a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p diving [ A*a(n)+B ] and p=2, A=2.00013, B=3.0.at n=9A029580
- Numbers whose base-4 representation has 4 fewer 0's than 3's.at n=19A031469
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 18.at n=40A031516
- Numbers k such that 203*2^k + 1 is prime.at n=13A032478
- a(n) = 2^n - 3.at n=11A036563
- a(n) = n*(2*n^2 - 3*n + 4)/3.at n=15A037235
- Bisection of A028289.at n=28A038390
- Sums of 10 distinct powers of 2.at n=9A038461