9123
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 12168
- Proper Divisor Sum (Aliquot Sum)
- 3045
- 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
- 6080
- Möbius Function
- 1
- Radical
- 9123
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 60
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(n) = s(1)s(n) + s(2)s(n-1) + ... + s(k)s(n+1-k), where k = [ (n+1)/2 ], s = (F(2), F(3), ...).at n=14A024591
- 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 95.at n=8A031593
- Number of partitions of n such that cn(0,5) = cn(1,5) <= cn(2,5) = cn(3,5) = cn(4,5).at n=74A036871
- Denominators of continued fraction convergents to sqrt(670).at n=9A042289
- Number of strongly unimodal partitions of n (strongly unimodal means strictly increasing then strictly decreasing).at n=31A059618
- Consider all sublists of [(2,1),(3,2,1),(4,3,2,1),...,(n,...,4,3,2,1)] and multiply these permutations in that order. How many of the products are n-cycles?at n=17A068330
- Numerator of 3 * H(n,3,2), a generalized harmonic number. See A075135.at n=4A074597
- Integers m such that the base-10 digit concatenation 2//m//3//m//5//m...//prime(49)//m//prime(50) is prime.at n=18A084048
- a(n) is the smallest number greater than a(n-1) such that in a(0) through a(n) no digit occurs more than once more than any other digit.at n=31A095204
- McKay-Thompson series of class 24b for the Monster group.at n=25A112162
- Where record values of A119999 occur.at n=30A120001
- Numbers k such that k and k^2 use only the digits 1, 2, 3, 8 and 9.at n=13A136984
- a(n) = n^3 + sum((-1)^j*a(j)); for j=1 to n-1; a(1)=1.at n=32A153286
- Numbers n such that n^3 - 4 and n^3 + 4 are prime.at n=35A161589
- Minimum number n, not already present, that permits the cyclic repetition of the decimal digits 1,2,3,4,5,6,7,8,9 in the sequence.at n=29A165307
- Positive integers of the form (2*m^2+1)/11.at n=40A179088
- Monotonic ordering of set S generated by these rules: if x and y are in S then (x+1)(y+1) is in S, and 2 is in S.at n=36A192518
- Number of 2 X 2 matrices with all terms in {0,1,...,n} and (sum of terms) = n+2.at n=34A210374
- Principal diagonal of the convolution array A213587.at n=7A213588
- Number of idempotent 3 X 3 0..n matrices of rank 2.at n=37A224334