9121
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 10432
- Proper Divisor Sum (Aliquot Sum)
- 1311
- 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
- 7812
- Möbius Function
- 1
- Radical
- 9121
- 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
- Number of distinct quadratic residues mod 10^n; also number of distinct n-digit endings of base-10 squares.at n=5A000993
- Numbers that are the sum of 11 positive 8th powers.at n=22A003389
- Pseudoprimes to base 95.at n=32A020223
- Pseudoprimes to base 96.at n=30A020224
- Strong pseudoprimes to base 95.at n=6A020321
- Strong pseudoprimes to base 96.at n=7A020322
- Numbers k such that Fib(k) == -13 (mod k).at n=33A023167
- Expansion of 1/((1-x)(1-6x)(1-10x)(1-12x)).at n=3A024435
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 52 ones.at n=20A031820
- Sizes of successive balls in E_8 lattice.at n=3A046948
- Expansion of ( 1-x ) / ( 1-x-x^2-x^4+x^5 ).at n=20A052989
- a(n) = A064842(n)/2.at n=37A064843
- Duplicate of A000993.at n=5A075759
- a(n) = n^3 - 7*n + 7.at n=20A106734
- French self-ranked numbers.at n=46A108987
- Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 111-110-111 pattern in any orientation.at n=11A146283
- Number of n X n binary arrays symmetric about the diagonal and under 90 degree rotation with all ones connected only in a 111-110-111 pattern in any orientation.at n=25A146285
- Number of nodes (or order) of a graph model obtained using an automata scheme on sets of order prime(n) >= 5 and in which all not halt states are linked by arcs (edges).at n=22A160772
- Numbers of the form k^2+k+1 that are the product of two distinct primes.at n=43A176069
- Concentric 24-gonal numbers.at n=39A195158