10891
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
- 1
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 10892
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10890
- Möbius Function
- -1
- Radical
- 10891
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 68
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- yes
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1325
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Expansion of g.f. 1/((1-3*x)*(1-5*x)*(1-7*x)).at n=4A017389
- Fibonacci sequence beginning 3, 16.at n=15A022126
- Smallest prime containing n-th square as substring.at n=33A029948
- Smallest nontrivial extension of n-th square which is a prime.at n=32A030685
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 64 ones.at n=17A031832
- Discriminants of imaginary quadratic fields with class number 19 (negated).at n=25A046016
- Primes p whose period of reciprocal equals (p-1)/9.at n=8A056214
- Prime lucky numbers k (from A031157) such that nextprime(k)=nextlucky(k).at n=18A057698
- Primes which, although they have correct parity, are not in the prime number maze.at n=14A065123
- Smallest prime containing the n-th square in decimal notation.at n=32A065144
- Smallest prime that begins with the n-th square in decimal notation.at n=32A065145
- a(n) = (11*n^2 - 11*n + 2)/2.at n=44A069125
- a(n), for n > 1, equals the least prime p such that p - a(n-1) is a cube, a(1)=2.at n=16A076201
- Column 1 of triangle A091604.at n=25A091611
- Triangle (read by rows) in which the number of entries in a row only increases by 1 every other row, the first column and the 'diagonal' is set to all 1's and a(i,j) = a(i-1,j) + a(i-1,j-1) + a(i-2,j-1) + a(i-3,j-1) for other entries.at n=54A096966
- Duplicate of A056214.at n=8A098676
- Primes of the form a^5 + b^3 with a,b>0.at n=19A100273
- a(n) equals the (n*(n+1)/2)-th partial sum of the self-convolution cube of A010054, which has the g.f.: Sum_{k>=0} x^(k*(k+1)/2).at n=27A109414
- Primes that are the difference of two Fibonacci numbers; primes in A007298.at n=27A113188
- Primes for which the weight as defined in A117078 is 23.at n=23A119504