4575
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 7688
- Proper Divisor Sum (Aliquot Sum)
- 3113
- 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
- 2400
- Möbius Function
- 0
- Radical
- 915
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 121
- 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
- Number of hybrid binary trees with n internal nodes.at n=6A007863
- Coordination sequence T2 for Zeolite Code GOO.at n=46A008112
- Triangle of numbers of hybrid rooted trees (divided by Fibonacci numbers).at n=21A011274
- Number of directed animals on a certain lattice.at n=6A011791
- Engel expansion of the golden ratio, (1 + sqrt(5))/2 = 1.61803... .at n=16A028259
- Number of partitions of n^3 into distinct cubes.at n=37A030272
- Decimal part of cube root of a(n) starts with 6: first term of runs.at n=14A034132
- Number of partitions of n into parts not of the form 25k, 25k+4 or 25k-4. Also number of partitions with at most 3 parts of size 1 and differences between parts at distance 11 are greater than 1.at n=31A036003
- Numbers k such that tau(sigma(k)) = tau(k) where tau(k) is the number of divisors of k and sigma(k) their sum.at n=47A037197
- a(n)=(s(n)+3)/9, where s(n)=n-th base 9 palindrome that starts with 6.at n=42A043077
- Numbers whose base-4 representation contains exactly three 1's and three 3's.at n=21A045127
- Numbers k that divide 8^k + 7^k.at n=42A045604
- Number of different values of i^2+j^2+k^2+l^2 for i,j,k,l in [ 0,n ].at n=37A047801
- Starting positions of strings of 2 7's in the decimal expansion of Pi.at n=39A050254
- Iterated procedure 'composite k added to sum of its prime factors reaches a prime' yields 8 skipped primes.at n=35A050775
- Numbers n such that n | sigma_10(n).at n=35A055714
- Engel expansion of sqrt(5) = 2.23606...at n=16A059176
- a(n) = (2*n - 1)*(7*n^2 - 7*n + 6)/6.at n=12A063490
- Number of Fibonacci numbers F(k), k <= 10^n, whose initial digit is 9.at n=4A073565
- Starting positions of strings of three 7's in the decimal expansion of Pi.at n=2A083631