4509
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 6720
- Proper Divisor Sum (Aliquot Sum)
- 2211
- 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
- 2988
- Möbius Function
- 0
- Radical
- 501
- Omega Function (Ω)
- 4
- 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
- 139
- 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
- Numbers that are the sum of 10 positive 7th powers.at n=22A003377
- Expansion of e.g.f.: tanh(log(1+x))*exp(x).at n=9A009778
- Composite n such that phi(n) * sigma(n) is one less than a square.at n=31A015709
- Odd composite n such that phi(n) * sigma(n) is one less than a square.at n=12A015722
- (s(n)+s(n+1))/6, where s()=A006521.at n=14A016059
- (s(n)+s(n+1))/18, where s()=A006521.at n=17A016060
- Lucky numbers with size of gaps equal to 14 (upper terms).at n=20A031897
- Positive numbers having the same set of digits in base 7 and base 9.at n=23A037439
- Starting index of a string of 3 or more consecutive equal digits in decimal expansion of Pi.at n=36A049515
- Starting index of a string of exactly 3 consecutive equal digits in decimal expansion of Pi.at n=30A049519
- Number of ordered pairs of integers (x,y) with x^2+y^2 < n^2.at n=38A051132
- Numbers k such that k | 12^k + 11^k + 10^k + 9^k + 8^k + 7^k + 6^k + 5^k + 4^k + 3^k + 2^k + 1^k.at n=44A057291
- Pinwheel numbers: a(n) = 2*n^2 + 6*n + 1.at n=46A059993
- Numbers whose decimal representations consist of nested and /or concatenated ordered pairs 0-9, 1-8, 2-7, 3-6 and 4-5.at n=39A065751
- a(n) = Sum_{d|n} phi(d^4).at n=9A068970
- Convoluted convolved Fibonacci numbers G_5^(r).at n=41A089109
- Number of elements e in all partitions of n such that e divides n.at n=22A089251
- E.g.f. equals the ratio of two power series, each with triangular exponents of x.at n=7A093615
- Number of partitions of the n-th abundant number into abundant numbers.at n=50A097800
- Minimal value of sum(p(i)p(i+1),i=1..n), where p(n+1)=p(1), as p ranges over all permutations of {1,2,...,n}.at n=28A110611