12909
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 18592
- Proper Divisor Sum (Aliquot Sum)
- 5683
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7920
- Möbius Function
- -1
- Radical
- 12909
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 107
- 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
- Number of B-trees of order 3 with n leaves.at n=27A014535
- a(n) = n*(17*n - 1)/2.at n=39A022274
- Number of A095282-primes in range ]2^n,2^(n+1)].at n=18A095292
- Number of partitions of n with exactly one prime number.at n=43A132381
- Numbers m with the property that its k-th smallest divisor, for all 1 <= k <= tau(m), contains exactly k "1" digits in its binary representation.at n=20A255401
- a(n) = 13*(2^n - 1) - 3*n^2 - 9*n.at n=9A257448
- a(1) = 6; for n > 1, a(n) = the least squarefree composite number whose sum of prime factors is prime and whose greatest prime factor is the sum of prime factors of a(n-1).at n=38A262081
- Numbers n such that n*2^2203 - 1 is prime.at n=16A265503
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 233", based on the 5-celled von Neumann neighborhood.at n=26A270978
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 633", based on the 5-celled von Neumann neighborhood.at n=6A273300
- Indices of records in A327008.at n=17A327010
- a(n) is the lowest number in the sequence of the first occurrence of exactly n consecutive numbers with at least one repeated digit, or -1 if no such number exists.at n=20A337707
- Numbers k whose ordered binary weights (A000120) of their divisors are the numbers 1 to A000005(k).at n=37A354724
- a(n) = Sum_{k=1..n} binomial(floor(n/k)+2,3).at n=38A364970
- Sum of the divisors of the n-th odd square: a(n) = sigma((2*n-1)^2).at n=46A379223