7806
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
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15624
- Proper Divisor Sum (Aliquot Sum)
- 7818
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 2600
- Möbius Function
- -1
- Radical
- 7806
- 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
- 176
- Smith Number
- no
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = C(n,1) + C(n,2) + C(n,3), or n*(n^2 + 5)/6.at n=36A004006
- Number of graphs on n nodes with 3 cliques.at n=17A005289
- Numbers k such that the continued fraction for sqrt(k) has period 56.at n=35A020395
- [ exp(7/16)*n! ].at n=6A030904
- Numbers having four 0's in base 6.at n=14A043372
- Numbers whose base-3 representation has exactly 9 runs.at n=32A043589
- Numbers n such that number of runs in the base 3 representation of n is congruent to 0 mod 9.at n=32A043806
- Numbers k such that number of runs in the base 3 representation of k is congruent to 9 mod 10.at n=32A043824
- Numbers k such that phi(k) + 1 = x^2 and sigma(k) + 1 = y^2 for some x and y.at n=39A063532
- Positive integers k such that k^20 + 1 is semiprime (A001358).at n=33A105282
- Number of partitions of n with at most 3 odd parts.at n=39A114312
- a(1) = 1; a(n) = max{ 5*a(k) + a(n-k) | 1 <= k <= n/2 } for n > 1.at n=33A130667
- Numbers k whose representation can be split in two parts which can be used as seeds for a Fibonacci-like sequence containing k itself.at n=46A130792
- Numbers k such that the numerator of the Bernoulli number B(2k) ends with the digits 691.at n=28A132184
- Triangle read by rows: T(n,k) = (4n-4k+1) * T(n-1,k-1) + (4k-3) * T(n-1,k).at n=22A142459
- Triangle read by rows: T(n,k) = (4n-4k+1) * T(n-1,k-1) + (4k-3) * T(n-1,k).at n=26A142459
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (0, 1, -1), (0, 1, 0), (1, 0, -1), (1, 1, 1)}.at n=7A150593
- Integers k such that (k^3)/3 is the average of a pair of twin primes.at n=43A152788
- Totally multiplicative sequence with a(p) = a(p-1) + 5 for prime p.at n=33A166702
- Numbers x such that 0 < |x^7 - y^2| < x^(5/2) for some number y.at n=6A173348