16920
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 56160
- Proper Divisor Sum (Aliquot Sum)
- 39240
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4416
- Möbius Function
- 0
- Radical
- 1410
- Omega Function (Ω)
- 7
- 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
- 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
- 84
- 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
- yes
- Odd
- no
Appears in sequences
- Expansion of e.g.f. (1+x)^(1-x).at n=10A007120
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 13.at n=9A031691
- Expansion of e.g.f. (1-x)/(1-3*x+x^3).at n=5A052693
- McKay-Thompson series of class 20F for Monster.at n=23A058555
- First differences of A069475, successive differences of (n+1)^6-n^6.at n=21A069476
- Coefficients of the polynomials in the numerator of the generating function f(x)=(x-x^2)/(x^3-2x^2-2x+1) for F(n)^2, (where F(n) is the Fibonacci sequence) and its successive derivatives starting with the constant.at n=37A079045
- Coefficients of the polynomials in the numerator of the generating function f(x)=(x-x^2)/(x^3-2x^2-2x+1) for F(n)^2, (where F(n) is the Fibonacci sequence) and its successive derivatives starting with the highest power of x.at n=45A079046
- Number of partitions of primes into mutual coprimes > 1.at n=34A086191
- Smallest number having exactly n divisors that are not greater than the number's greatest prime factor.at n=18A087134
- Values of n for which A095777(n) is 16 (those terms which are expressible in decimal digits for bases 2 through 17, but not for base 18).at n=16A095785
- Expansion of chi(-q)^5 / chi(-q^5) in powers of q where chi() is a Ramanujan theta function.at n=22A138521
- a(0)=360, a(n)=a(n-1)+720 for n>=1.at n=23A140801
- Smallest multiple of n with a number of divisors >= n.at n=46A140965
- a(n) = 169*n^2 + 2*n.at n=9A158220
- Generalized Pascal Triangle - satisfying the same recurrence as Pascal's triangle, but with a(n,0)=1 and a(n,n)=10^n (instead of both being 1).at n=49A164844
- Numbers n for which the terms of the multiplicative sequence {n^2/A049417(n)} are integers.at n=23A185288
- Number of nX6 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=4A207760
- T(n,k)=Number of nXk 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=49A207762
- Number of 5Xn 0..1 arrays avoiding 0 0 0 and 1 0 1 horizontally and 0 1 1 and 1 0 1 vertically.at n=5A207765
- Expansion of chi(q)^5 / chi(q^5) in powers of q where chi() is a Ramanujan theta function.at n=22A225701