2205
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 18
- Divisor Sum
- 4446
- Proper Divisor Sum (Aliquot Sum)
- 2241
- 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
- 1008
- Möbius Function
- 0
- Radical
- 105
- 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
- no
Recreational
- Happy Number
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 45
- 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
- no
- Odd
- yes
Appears in sequences
- Heptagonal numbers (or 7-gonal numbers): n*(5*n-3)/2.at n=30A000566
- Associated Mersenne numbers.at n=16A001350
- MacMahon's generalized sum of divisors function.at n=23A002127
- Expansion of a modular function for Gamma_0(21).at n=16A002511
- a(n) = (4*n+1)*(4*n+5).at n=11A003185
- Alternate Lucas numbers - 2.at n=8A004146
- a(n) = ceiling(n*phi^9), where phi is the golden ratio, A001622.at n=29A004964
- Sum of cubes of primes dividing n.at n=25A005064
- Sum of cubes of primes dividing n.at n=51A005064
- Odd abundant numbers (odd numbers m whose sum of divisors exceeds 2m).at n=2A005231
- Primitive pseudoperfect numbers.at n=36A006036
- Odd primitive abundant numbers.at n=2A006038
- Primitive nondeficient numbers.at n=29A006039
- a(n) = Sum_{k=1..n-1} lcm(k,n-k).at n=30A006580
- Coordination sequence T1 for Zeolite Code CHA.at n=36A008066
- Coordination sequence T2 for Zeolite Code MTT.at n=29A008190
- a(n) = n OR n^3 (applied to binary expansions).at n=12A008468
- Molien series for A_4.at n=52A008627
- Molien series for A_5.at n=39A008628
- Number of increasing sequences of addition chain type with maximal element n.at n=14A008928