2145
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 4032
- Proper Divisor Sum (Aliquot Sum)
- 1887
- 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
- 960
- Möbius Function
- 1
- Radical
- 2145
- 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
- yes
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- yes
- 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
- 76
- 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
- no
- Odd
- yes
Appears in sequences
- Number of 4-dimensional partitions of n.at n=7A000334
- Hexagonal numbers: a(n) = n*(2*n-1).at n=33A000384
- Number of unlabeled connected loop-less graphs on n nodes containing exactly one cycle (of length at least 2) and with all nodes of degree <= 4.at n=10A002094
- Nearest integer to 4 * Pi * n^3 / 3.at n=8A002101
- 4-dimensional figurate numbers: a(n) = (6*n-2)*binomial(n+2,3)/4.at n=8A002419
- Odd squarefree numbers with an even number of prime factors that have no prime factors greater than 31.at n=50A002557
- Binomial coefficient C(6n,n-9).at n=2A004364
- From paths in the plane.at n=3A006859
- a(n) = floor(n*(n+2)*(2*n-1)/8).at n=19A007518
- Coordination sequence T1 for Zeolite Code AEI.at n=35A008001
- Coordination sequence T3 for Zeolite Code AFT.at n=35A008028
- Coordination sequence T1 for Zeolite Code AWW.at n=33A008045
- Coordination sequence T4 for Zeolite Code DDR.at n=29A008074
- Coordination sequence T1 for Zeolite Code EMT.at n=38A008086
- Expansion of Jacobi theta constant theta_2^6 /(64q^(3/2)).at n=32A008440
- Expansion of (1+x^12)/((1-x)*(1-x^2)*(1-x^3)*(1-x^4)).at n=54A008773
- Coordination sequence T1 for Zeolite Code RTH.at n=32A009893
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 3.at n=22A013591
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 4.at n=3A013592
- Orders of cyclotomic polynomials containing a coefficient the absolute value of which is >= 5.at n=1A013593