1649
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1764
- Proper Divisor Sum (Aliquot Sum)
- 115
- 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
- 1536
- Möbius Function
- 1
- Radical
- 1649
- 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
- 29
- 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
- a(n) = 4^n + n^4.at n=5A001589
- a(n) = 5^n + n^5.at n=4A001593
- Sums of distinct nonzero 4th powers.at n=45A003999
- Expansion of g.f.: (1+x^3)*(1+x^4)/((1-x)*(1-x^2)^2*(1-x^4)).at n=33A004657
- Odd numbers not of form p + 2^k (de Polignac numbers).at n=33A006285
- a(n) = (n^3 + 2*n)/3.at n=17A006527
- Coordination sequence T1 for Zeolite Code AFI.at n=28A008014
- Coordination sequence T1 for Zeolite Code KFI.at n=31A008123
- Coordination sequence T6 for Zeolite Code MFI.at n=26A008169
- Smallest odd k>n such that k | n^k + n, or 0 if n=2^m.at n=34A015908
- Pseudoprimes to base 8.at n=27A020137
- Pseudoprimes to base 12.at n=12A020140
- Pseudoprimes to base 18.at n=17A020146
- Pseudoprimes to base 22.at n=16A020150
- Pseudoprimes to base 27.at n=17A020155
- Pseudoprimes to base 33.at n=11A020161
- Pseudoprimes to base 47.at n=24A020175
- Pseudoprimes to base 50.at n=19A020178
- Pseudoprimes to base 70.at n=14A020198
- Pseudoprimes to base 75.at n=15A020203