10991
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 11400
- Proper Divisor Sum (Aliquot Sum)
- 409
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10584
- Möbius Function
- 1
- Radical
- 10991
- 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
- 99
- 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 86.at n=42A020214
- Strong pseudoprimes to base 94.at n=12A020320
- Conjecturally, number of infinitely-recurring prime patterns on n consecutive integers.at n=33A023192
- An "extremely strange sequence": a(n+1) = [ A*a(n)+B ]/p^r, where p^r is the highest power of p dividing [ A*a(n)+B ] and p=2, A=4.001, B=1.2.at n=28A028948
- BIK(b)-b where b is A035082.at n=14A035084
- Numbers whose base-4 representation contains exactly four 2's and three 3's.at n=1A045156
- a(n) = Sum_{i=0..n} T(i,n-i), array T as in A049747.at n=32A049748
- The n-th n-gonal number: a(n) = n*(n^2 - 3*n + 4)/2.at n=29A060354
- Composite numbers whose divisors (except 1) all contain the digit 9.at n=19A062680
- Numbers k such that Euler phi(k) / Carmichael lambda(k) = 14.at n=23A066696
- Numbers k such that sigma(k) divides sigma(phi(k)).at n=37A066831
- Numbers n such that sigma(phi(n))/sigma(n) = 3.at n=4A067383
- Semiprimes that are the sum of two positive cubes. Common terms of A003325 and A046315.at n=38A085366
- Odd numbers n such that there exists a solution to lcm(s,z-s) = n, lcm(t,z-t) = n-2 and 0 < s+t < z < n.at n=35A108157
- Numbers k such that k and k^2 use only the digits 0, 1, 2, 8 and 9.at n=60A136835
- Partial sums of A002503.at n=43A176358
- Numbers which are the sum of two positive cubes and divisible by 29.at n=7A224483
- G.f.: Sum_{n>=0} x^n * Sum_{k=0..n} binomial(n,k)^3 * x^(2*k).at n=11A248658
- Number of (n+2)X(1+2) 0..4 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=0A252033
- T(n,k)=Number of (n+2)X(k+2) 0..4 arrays with every 3X3 subblock row and column sum nonprime and every diagonal and antidiagonal sum prime.at n=0A252039