7809
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 11040
- Proper Divisor Sum (Aliquot Sum)
- 3231
- 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
- 4896
- Möbius Function
- -1
- Radical
- 7809
- Omega Function (Ω)
- 3
- 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
- 145
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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
- Numbers that are the sum of 3 positive 5th powers.at n=35A003348
- Numbers whose base-3 representation has exactly 9 runs.at n=34A043589
- Numbers n such that number of runs in the base 3 representation of n is congruent to 0 mod 9.at n=34A043806
- Numbers k such that number of runs in the base 3 representation of k is congruent to 9 mod 10.at n=34A043824
- Sizes of successive clusters in Z^4 lattice.at n=39A046895
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2*n - 2 - 2^(p+1) and p is the unique integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 3, and a(3) = 2.at n=16A049923
- a(n) = (n^3 + 5*n + 18)/6.at n=38A060163
- Numbers k such that the smoothly undulating palindromic number (4*10^k-7)/33 = 121...21 is a prime (or PRP).at n=8A062209
- a(n) = 1^n + 2^n + 6^n.at n=5A074502
- Expansion of (1-x)^(-1)/(1-2*x^2+2*x^3).at n=18A077881
- a(n) = ((n^6 - (n-1)^6) - (n^2 - (n-1)^2))/60.at n=9A079547
- a(n) = (prime(n)^4 - 1) / 240.at n=8A089034
- Starting numbers for which the RATS sequence has eventual period 14.at n=9A114615
- a(n) = J_4(n)/240.at n=31A115002
- Numbers k such that k*(k+2) gives the concatenation of a number m with itself.at n=7A116286
- Grow a binary tree using the following rules. Initially there is a single node labeled 1. At each step we add 1 to all labels less than 3. If a node has label 3 and zero or one descendants we add a new descendant labeled 1. Sequence gives sum of all labels at step n.at n=38A123015
- a(n) is equal to the number of positive integers m less than or equal to 10^n such that m is not divisible by the prime 5 and is not divisible by at least one of the primes 2, 3 and 7.at n=2A128951
- Wiener index of the hexagon crown (beehive model) with n hexagons on each side of the outside ring.at n=2A143366
- a(n) = (2*n^3 + 5*n^2 + 5*n)/2.at n=18A162267
- Symmetrical triangle T(n, m) = floor(Eulerian(n+1, m)/2), read by rows.at n=17A174098