9642
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
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19296
- Proper Divisor Sum (Aliquot Sum)
- 9654
- 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
- 3212
- Möbius Function
- -1
- Radical
- 9642
- 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
- 21
- 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(1) = a(2) = 1, a(3) = 4; thereafter a(n) = a(n-1) + a(n-3).at n=23A001609
- Energy function for hexagonal lattice.at n=9A007239
- Numbers whose base-2 representation has exactly 12 runs.at n=22A043579
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=3, r=3, I={1}.at n=11A079996
- Number of 8k+1 primes (A007519) in range ]2^n,2^(n+1)].at n=18A095009
- Iccanobirt prime indices (9 of 15): Indices of prime numbers in A102119.at n=11A102139
- Trisection of A107926: The least number k such that there are primes p and q with p - q = 6*n+2, p + q = k, and p the least such prime >= k/2.at n=29A234955
- a(n) = 7*n^2 + 2*n - 15.at n=36A239796
- Zeroless numbers n whose digit product squared is equal to the digit product of n^2.at n=9A256115
- Number of independent vertex sets and vertex covers in the n-antiprism graph.at n=12A286910
- Growth series for group with presentation < S, T : S^2 = T^3 = (S*T)^10 = 1 >.at n=26A298812
- a(n) = Sum_{i=1..n} sigma(i)*sigma(i+1), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=21A330322
- Numbers of graphs which are double triangle descendants of K_5 with four more vertices than triangles.at n=26A332735
- Numbers k such that A338338(k) is a prime p that ends a run of three terms in A338338 that are divisible by p.at n=28A338344
- a(n) = round(c^n), where c is the supergolden ratio A092526.at n=24A382641