9209
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 9210
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 9208
- Möbius Function
- -1
- Radical
- 9209
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 122
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1142
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that (3^k + 1)/4 is prime.at n=14A007658
- Numbers k such that the continued fraction for sqrt(k) has period 75.at n=3A020414
- Primes that remain prime through 3 iterations of function f(x) = 8x + 7.at n=6A023294
- Primes of the form k^2 - 7.at n=11A028883
- Primes with first digit 9.at n=39A045715
- Number of 8 X 8 binary matrices with n=0..64 ones up to row and column permutations.at n=11A053305
- Primes p with property that p concatenated with its emirp p' (prime reversal) forms a palindromic prime of the form 'primemirp' (rightmost digit of p and leftmost digit of p' are blended together - p and p' palindromic allowed).at n=45A054217
- Primes starting and ending with 9.at n=7A062335
- Smallest k such that f(f(...f(k))) > 1, where f(k) = A065371(k) is iterated n times.at n=8A065374
- Primes p such that p+7 == 0 (mod phi(p+7)).at n=24A067606
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,1,3}.at n=43A079957
- Primes p such that 8p +1 and (p-1)/8 are primes.at n=7A085958
- Smallest prime obtained as a sum of n terms of a geometric progression + the common ratio, or 0 if no such terms exists. Smallest prime of the form (a +ar +ar^2 + ar^3 +... ) + r.at n=9A088121
- Primes from merging of 4 successive digits in decimal expansion of Pi.at n=32A104824
- Primes from merging of 5 successive digits in decimal expansion of Pi.at n=25A104825
- Emirps starting and ending with composite digit 9.at n=1A128374
- Canyon primes.at n=26A134971
- Prime numbers p such that p^3 - (p+1)^2 and p^3 + (p+1)^2 are both primes.at n=10A137476
- Primes of the form 41*x^2+38*x*y+41*y^2.at n=36A140013
- Primes of the form 21x^2+65y^2.at n=35A140023