11257
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 11258
- 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
- 11256
- Möbius Function
- -1
- Radical
- 11257
- 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
- 112
- 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
- 1361
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Numbers k such that (3^k + 1)/4 is prime.at n=15A007658
- Numbers k such that the continued fraction for sqrt(k) has period 3.at n=29A013643
- a(n) = number of (s(0), s(1), ..., s(n)) such that every s(i) is a nonnegative integer, s(0) = 0, s(1) = 1, |s(i) - s(i-1)| <= 1 for i >= 2. Also a(n) = sum of numbers in row n+1 of the array T defined in A026105. Also a(n) = T(n,n), where T is the array defined in A025564.at n=11A025566
- Numbers k such that the continued fraction for sqrt(k) has odd period and if the last term of the periodic part is deleted then there are a pair of central terms both equal to 10.at n=14A031423
- Least term in period of continued fraction for sqrt(n) is 10.at n=22A031434
- Positive numbers having the same set of digits in base 8 and base 10.at n=36A037442
- Numbers n such that n and n+4^k are all primes for k=1,2,3.at n=25A049493
- Numbers n such that 2^n - 21 is prime.at n=25A057202
- Primes p such that x^67 = 2 has no solution mod p.at n=21A059330
- Primes with 10 as smallest positive primitive root.at n=31A061323
- Square array read by antidiagonals: number of ways a pawn-like piece (with the initial 2-step move forbidden and starting from any square on the back rank) can end at various squares on an infinite chessboard.at n=64A062105
- Smallest d such that real quadratic field with discriminant d has class number n.at n=16A081364
- a(1) = 1, a(2) = 2 and a(n) = smallest number not included earlier that divides the concatenation a(n-2), a(n-1).at n=9A085946
- Numbers which are primes and which remain prime for three successive applications of incrementing each digit by 2 with carries ignored.at n=17A088787
- Primes of the form 6*p - 5 such that p and 6*p - 1 are primes.at n=41A090607
- Numbers k such that p(k), p(k)+6, p(k)+12, p(k)+18 are consecutive primes, where p(k) denotes k-th prime.at n=42A090832
- Numbers n such that p(n),p(n)+6,p(n)+12,p(n)+18 are consecutive primes and p(n)=6*k+1 for some k, where p(n) denotes n-th prime.at n=21A090838
- Numbers k such that 2^k - 21 is prime.at n=21A096820
- Triangle read by rows: T(n,k) is the number of ordered trees with n edges and having k branches of odd length (n>=0, 0<=k<=n).at n=75A102003
- Primes p such that little googol + p is prime.at n=24A108255