12009
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 16016
- Proper Divisor Sum (Aliquot Sum)
- 4007
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8004
- Möbius Function
- 1
- Radical
- 12009
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 81
- 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
- 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 72.at n=38A031570
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 64 ones.at n=23A031832
- Decimal part of cube root of n starts with 9: first term of runs.at n=21A034135
- Numbers having four 3's in base 6.at n=29A043384
- Becomes prime after exactly 7 iterations of f(x) = sum of prime factors of x.at n=22A047826
- Numbers n such that 5*10^n + 8*R_n - 7 is prime, where R_n = 11...1 is the repunit (A002275) of length n.at n=10A103022
- a(n) = 8*n^2 - 4*n - 3.at n=38A118057
- Indices k such that 19 plus the k-th triangular number is a perfect square.at n=9A154147
- a(n) = number of n-lettered words in the alphabet {1, 2, 3} with as many occurrences of the substring (consecutive subword) [1, 1, 2] as of [1, 3, 1].at n=9A211291
- Number of integer partitions of n containing no part > 1 whose prime indices all belong to the partition.at n=48A324754