7704
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 21060
- Proper Divisor Sum (Aliquot Sum)
- 13356
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 2544
- Möbius Function
- 0
- Radical
- 642
- Omega Function (Ω)
- 6
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 52
- 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
- yes
- Odd
- no
Appears in sequences
- Number of partitions of n into parts of 8 kinds.at n=6A023007
- Let c(k) denote the k-th composite number and p(k) the k-th prime number; then a(n) = Sum_{i=n*(n-1)/2+1 .. n*(n+1)/2} c(i) - Sum_{i=1..n} p(i).at n=23A024850
- 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 21.at n=38A031519
- Four times pentagonal numbers: a(n) = 2*n*(3*n-1).at n=36A033579
- Differences between numbers k such that k and k+1 have the same sum of divisors.at n=35A054001
- Numbers k such that phi(x) = k has exactly 9 solutions.at n=40A060672
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 83 ).at n=27A063356
- a(n) = sum of modular offsets: mod[n+c,b]-(mod[n,b]+c) for c<=b<=n.at n=40A066809
- Index of the primes in A084165.at n=15A084166
- Number of n-vertex unlabeled digraphs without endpoints.at n=5A101388
- Positive integers i for which A112049(i) == 7.at n=17A112067
- Sum_{k=1..n} k*a(k) is a Fibonacci number. a(n) = A112365(n)/n.at n=5A112366
- Triangle T(n, k) = k^2*(1+n)^2 - 4*n, read by rows.at n=63A123961
- 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), (-1, 1, -1), (1, -1, -1), (1, 1, 0), (1, 1, 1)}.at n=7A150678
- Number of different fixed (possibly) disconnected trominoes bounded (not necessarily tightly) by an n*n square.at n=8A162673
- Number of scalene triangles, distinct up to congruence, on an n X n grid (or geoboard).at n=14A190313
- [s(k)-s(j)]/6, where the pairs (k,j) are given by A205857 and A205858, and s(k) denotes the (k+1)-st Fibonacci number.at n=37A205860
- Number of nondecreasing sequences of 3 1..n integers with no element dividing the sequence sum.at n=38A212870
- Sum of the denominators of the Farey series of order n (A006843).at n=33A240877
- Number of terms of A072873 less than or equal to 10^n.at n=32A267757