12871
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 13144
- Proper Divisor Sum (Aliquot Sum)
- 273
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12600
- Möbius Function
- 1
- Radical
- 12871
- 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
- 169
- 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
- Pseudoprimes to base 14.at n=37A020142
- Pseudoprimes to base 15.at n=22A020143
- Pseudoprimes to base 74.at n=43A020202
- Pseudoprimes to base 77.at n=39A020205
- Strong pseudoprimes to base 83.at n=11A020309
- Numbers k such that the continued fraction for sqrt(k) has period 88.at n=38A020427
- Odd 9-gonal (or enneagonal) numbers.at n=30A028991
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 37 ones.at n=0A031805
- a(n) = (2*n+1)*(7*n+1).at n=30A033572
- Gaps of 10 in sequence A038593 (lower terms).at n=9A038659
- Numbers ending with '1' that are the difference of two positive cubes.at n=42A038856
- a(n) = binomial(n, floor(n/2)) + 1.at n=16A051920
- Numbers k such that k | sigma_11(k) - phi(k)^11.at n=13A055705
- Centered 13-gonal numbers.at n=44A069126
- Largest proper divisor of the n-th Carmichael number (A002997).at n=28A081703
- Solution to the non-squashing boxes problem (version 1).at n=34A089054
- Triangle read by rows: number of atomic set compositions of size n and length k (see description in A095989) 1 <= k <= n.at n=25A109062
- Semiprimes in A003215.at n=26A113530
- n-th term of the Fibonacci-type sequence x(1)=1, x(2)=Fibonacci(n), x(k+1)=x(k)+x(k-1) for k>1.at n=11A142975
- a(n) = 12*n^2 + 18*n + 7.at n=32A154105