9205
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 12672
- Proper Divisor Sum (Aliquot Sum)
- 3467
- 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
- 6288
- Möbius Function
- -1
- Radical
- 9205
- 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
- 47
- 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
- 4-dimensional analog of centered polygonal numbers.at n=13A006322
- Fibonacci sequence beginning 5, 12.at n=15A022137
- a(n) = n*(15*n + 1)/2.at n=35A022273
- a(n) = Sum_{i=0..2n} (-1)^i * T(i,2n-i), array T as in A049735.at n=27A049737
- One-sixtieth of the even leg of Pythagorean triangles whose other sides are both primes (other than 3, 5 or 13).at n=32A068485
- Sums of groups in A075639.at n=14A075640
- Numbers k such that average of prime(k) and prime(k+1) is a perfect square.at n=39A076692
- Numbers k such that numerator of Sum_{i=1..k} 1/(prime(i)-1) is prime.at n=58A092063
- Numbers k such that 2*10^k+9 is prime.at n=6A101392
- a(n) = 6*n^2 - 10*n + 5.at n=39A136392
- Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 1010-1111-1010 pattern in any orientation.at n=15A147442
- 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, 0, 1), (0, 1, 1), (1, 0, -1), (1, 0, 1)}.at n=7A150607
- Products of 3 distinct safe primes.at n=23A157354
- a(n) = n*(n+1)*(20*n-17)/6.at n=14A172117
- G.f. satisfies: A(x) = 1 + Sum_{n>=1} q^(2n-1)/(1 - q^(2n-1)) where q = x*A(x).at n=9A190790
- Maximum deviation from n in Collatz trajectory of n.at n=26A213538
- Number of length n+2 0..2 arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=6A253123
- T(n,k)=Number of length n+2 0..k arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=34A253129
- Number of length 7+2 0..n arrays with the sum of medians of adjacent triples multiplied by some arrangement of +-1 equal to zero.at n=1A253135
- Numbers n with the property that it is possible to write the base 2 expansion of n as concat(a_2,b_2), with a_2>0 and b_2>0 such that, converting a_2 and b_2 to base 10 as a and b, we have antisigma(a) + antisigma(b) = n.at n=8A259670