1129
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 1130
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1128
- Möbius Function
- -1
- Radical
- 1129
- 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
- 36
- 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
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 189
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts.at n=47A000124
- a(0)=2; for n>=1, a(n) = smallest prime p such that there is a gap of exactly 2n between p and next prime, or -1 if no such prime exists.at n=11A000230
- Number of points of norm <= n^2 in square lattice.at n=19A000328
- Primes p of the form 3k+1 such that -sqrt(p) < sum_{x=1..p} cos(2*Pi*x^3/p) < sqrt(p).at n=25A000922
- a(n) = least value of m for which Liouville's function A002819(m) = -n.at n=39A002053
- From a Goldbach conjecture: records in A185091.at n=19A002092
- Primes p == 1 (mod 4) where class number of Q(sqrt p) increases.at n=4A002142
- Primes (lower end) with record gaps to the next consecutive prime: primes p(k) where p(k+1) - p(k) exceeds p(j+1) - p(j) for all j < k.at n=8A002386
- Increasing gaps between prime-powers.at n=11A002540
- Primes p with a Fibonacci primitive root g, i.e., such that g^2 = g + 1 (mod p).at n=50A003147
- Number of restricted 3 X 3 matrices with row and column sums n.at n=24A005045
- Class 4+ primes (for definition see A005105).at n=17A005108
- Sequence and first differences (A030124) together list all positive numbers exactly once.at n=42A005228
- Primes of the form m^2 + 3m + 9, where m can be positive or negative.at n=15A005471
- a(n) = Sum_{k=1..n-1} (k OR n-k).at n=36A006583
- Discriminants of totally real cubic fields.at n=30A006832
- Inverse Moebius transform of triangular numbers.at n=46A007437
- Number of subsequences of [ 1,...,n ] in which each even number has an odd neighbor.at n=11A007481
- a(n) = 3*a(n-1) + 2*a(n-2), with a(0)=2, a(1)=7.at n=5A007484
- Primes of form 8n+1, that is, primes congruent to 1 mod 8.at n=41A007519