8787
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 30
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12240
- Proper Divisor Sum (Aliquot Sum)
- 3453
- 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
- 5600
- Möbius Function
- -1
- Radical
- 8787
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 140
- 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
- Expansion of (psi(x^2) / psi(-x))^3 in powers of x where psi() is a Ramanujan theta function.at n=13A001937
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 31.at n=31A031529
- Lucky numbers that are concatenations of a number k with itself.at n=9A032650
- A Diaconis-Mosteller approximation to the Birthday problem function.at n=39A050255
- Sums of members of groups in A076062.at n=25A076060
- Number of different solutions to a variant of the 3-ball tennis ball problem.at n=4A079486
- a(n) is the largest base-9 string such that the n-th number coprime to 9 does not divide any substring of a(n).at n=2A114911
- Fixed points of permutation A113821.at n=3A115640
- n times n+3 gives the concatenation of two numbers m and m+7.at n=4A116336
- Number of n X n binary arrays with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.at n=7A147123
- Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.at n=16A147125
- Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a 1000-1000-1111-1000 pattern in any orientation.at n=17A147125
- a(n) = 338*n - 1.at n=25A157999
- a(n) = 676*n - 1.at n=12A158393
- a(n) = 52*n^2 - 1.at n=12A158640
- Number of n X n matrices over {0,1} with rows and columns summing to 3, rows and columns sorted (>=) by value.at n=8A181344
- Numbers without digit 0 or 5 whose "waterfall sequence" ends in 0,0,0,...at n=36A210614
- T(n,k) = Number of (n+k-1) X (n+k-1) binary arrays with k 1s in every row and column with rows and columns in lexicographically nondecreasing order.at n=39A227061
- The number of partitions of n into at least 3 parts from which we can form every partition of n into 3 parts by summing elements.at n=36A236970
- Numbers x such that sigma(x) + sigma(R(x)) = sigma(x + R(x)), where R(x) is the digit reversal of x and sigma(x) is the sum of the divisors of x.at n=15A246487