7665
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
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 14208
- Proper Divisor Sum (Aliquot Sum)
- 6543
- 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
- 3456
- Möbius Function
- 1
- Radical
- 7665
- Omega Function (Ω)
- 4
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 57
- 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
- no
- Odd
- yes
Appears in sequences
- Number of loopless rooted planar maps with 3 faces and n vertices and no isthmuses. Also a(n)=T(4,n-3), array T as in A049600.at n=32A006416
- sec(log(x+1)-arcsinh(x))=1+3/4!*x^4-30/5!*x^5+180/6!*x^6-945/7!*x^7...at n=8A013280
- Number of ordered 5-tuples of integers from [ 1,n ] with no common factors among pairs.at n=28A015663
- Pseudoprimes to base 22.at n=38A020150
- a(n) = n*(17*n + 1)/2.at n=30A022275
- a(n) = (d(n)-r(n))/5, where d = A026043 and r is the periodic sequence with fundamental period (0,2,3,0,0).at n=45A026045
- The sequence e when b=[ 1,1,0,1,1,... ].at n=46A042955
- a(n)=T(2n-1,n), array T given by A048212.at n=45A048221
- a(0) = 0; a(n) is obtained by incrementing each digit of a(n-1) by 1.at n=25A061511
- A multiplicative version of 2^n - 1 (A000225).at n=35A064084
- Numbers k that divide 2^(k+3) - 1.at n=36A069927
- 2-nadirs of phi: numbers k such that phi(k-2) > phi(k-1) > phi(k) < phi(k+1) < phi(k+2).at n=40A076773
- Even order Taylor coefficients at x = 0 of exp(-x^2/(x^2-2)), odd order coefficients being equal to zero.at n=4A081020
- Maximum cycle size in range [A014137(n-1)..A014138(n-1)] of permutation A071665/A071666.at n=15A089874
- a(n) = (Sum_{k=1..n} A073698(k))^(1/n).at n=47A093928
- Smallest number not occurring earlier fitting the repeating pattern "99887766554433221100".at n=41A098782
- Number of partitions of n with no part larger than n/2. Also partitions of n into n/2 or fewer parts.at n=32A110618
- Numbers k such that k * (k + 7) is the concatenation of a number m with itself.at n=5A116291
- Increasing gaps in the even sieve (A056533) by lower term.at n=17A119503
- Numbers k for which nontrivial positive magic squares of exactly 8 different orders with magic sum k exist. For a definition of nontrivial positive magic squares, see A125005.at n=39A125015