17903
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
- 2
- Divisor Sum
- 17904
- 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
- 17902
- Möbius Function
- -1
- Radical
- 17903
- 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
- 97
- 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
- yes
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 2051
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- The lexicographically earliest sequence of binary encodings of solutions satisfying the equation p_i = (1+mod(i,2))*p_{i-1} +- p_{i-2} +- p_{i-3} +- ... +- 2 + 1, where p_i is the i-th prime number.at n=14A059874
- Append more digits to the n-th prime (leading zeros are permitted) until another prime is reached.at n=40A064792
- Primes congruent to 42 mod 53.at n=36A142572
- Primes congruent to 26 mod 59.at n=31A142753
- Primes congruent to 30 mod 61.at n=33A142828
- a(0)=113, then a(n) = smallest prime p not already used such that the first three digits of p = the last three digits of a(n-1).at n=24A175687
- a(n) = prime number > a(n-1) that contains the n-th prime as a substring.at n=40A177981
- Triangle T(n,k) read by rows: the coefficient [x^k] of the product_{s=1..n} (x+16*cos(s*Pi/(2n+1))^4), 0<=k<=n.at n=40A179837
- Magnetic Tower of Hanoi, number of moves of disk number k, optimally solving the [RED ; BLUE ; NEUTRAL] or [NEUTRAL ; RED ; BLUE] pre-colored puzzle.at n=10A183111
- Number of zero-sum n X 2 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.at n=3A201955
- Number of zero-sum nX4 -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.at n=1A201957
- T(n,k)=Number of zero-sum nXk -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.at n=11A201958
- T(n,k)=Number of zero-sum nXk -3..3 arrays with every element unequal to at most two horizontal and vertical neighbors.at n=13A201958
- Primes that are the sum of 25 consecutive primes.at n=24A215991
- a(n) = n*prime(prime(n)) - prime(n)^2.at n=47A230098
- Indices of primes in A214830.at n=14A244001
- Primes p such that prime(p)^2 - 2 = prime(q) for some prime q.at n=18A261354
- T(n,k)=Number of nXk 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=58A303410
- Number of 4Xn 0..1 arrays with every element equal to 1, 2, 4, 5 or 6 horizontally, diagonally or antidiagonally adjacent elements, with upper left element zero.at n=7A303411
- a(n) is the least prime p such that p^(2*n+1) == 2*n+1 (mod 2^(2*n+1)).at n=7A339758