1661
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 1824
- Proper Divisor Sum (Aliquot Sum)
- 163
- 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
- 1500
- Möbius Function
- 1
- Radical
- 1661
- 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
- 135
- 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
- Prime numbers of measurement.at n=38A002049
- Divisors of 2^30 - 1.at n=25A003538
- Expansion of (1-x+x^2)/((1-x)^2*(1-x^2)*(1-x^4)).at n=40A005232
- Centered dodecahedral numbers.at n=5A005904
- Number of elements in Z[ sqrt(-2) ] whose 'smallest algorithm' is <= n.at n=14A006459
- Coordination sequence T1 for Zeolite Code APD.at n=27A008034
- Coordination sequence T2 for Zeolite Code APD.at n=27A008035
- Coordination sequence T4 for Zeolite Code BOG.at n=29A008052
- Coordination sequence T2 for Zeolite Code LAU.at n=29A008125
- Expansion of e.g.f. exp(sinh(x)*cosh(x)).at n=7A009229
- Coordination sequence T5 for Zeolite Code DFO.at n=31A009879
- a(n) = n^2 - floor( n/2 ).at n=41A014848
- Row sums of triangle A004747.at n=4A015735
- Positive integers n such that 2^n == 2^11 (mod n).at n=35A015935
- Powers of cube root of 24 rounded down.at n=7A018045
- Powers of cube root of 24 rounded to nearest integer.at n=7A018046
- Powers of fourth root of 3 rounded down.at n=27A018051
- Cycle class sequence c(n) (the number of true cycles of length n in which a certain node is included) for zeolite BEA = Beta Na7[Al7Si57O128] starting with a T2 atom.at n=10A019068
- Pseudoprimes to base 8.at n=28A020137
- Pseudoprimes to base 19.at n=17A020147