1723
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
- 1724
- 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
- 1722
- Möbius Function
- -1
- Radical
- 1723
- 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
- 55
- 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
- 269
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- a(n) = least m such that if a/b < c/d where a,b,c,d are integers in [0,n], then a/b < k/m < c/d for some integer k.at n=47A001000
- Number of sublattices of index n in generic 3-dimensional lattice.at n=40A001001
- Primes p such that the multiplicative order of 2 modulo p is (p-1)/3.at n=23A001133
- Central polygonal numbers: a(n) = n^2 - n + 1.at n=42A002061
- Numbers k such that 21*2^k - 1 is prime.at n=16A002238
- Primes of form k^2 + k + 1.at n=16A002383
- Primes of form (p^x - 1)/(p^y - 1), p prime.at n=12A003424
- Least m such that if a/b < c/d are Farey fractions of order n then there exists k such that a/b < k/m < c/d, k/m reduced.at n=47A009571
- Primes of the form x^2 + 27y^2.at n=38A014752
- Numbers k=3*m+1 such that 2^m == 1 (mod k).at n=39A016108
- Powers of fourth root of 2 rounded up.at n=43A018050
- Numbers k such that the continued fraction for sqrt(k) has period 38.at n=9A020377
- Largest value of k for which Golay-Rudin-Shapiro sequence A020986(k) = n.at n=37A020991
- Prime numbers that are the sum of the divisors of some n.at n=7A023195
- Primes that remain prime through 2 iterations of function f(x) = 10x + 9.at n=30A023270
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = A023532, t = A001950 (upper Wythoff sequence).at n=46A024374
- Least m such that if r and s in {Pi/2 - atn(h): h = 1,2,...,n} satisfy r < s, then r < k/m < s for some integer k.at n=46A024832
- a(n) = least m such that if r and s in {1/2, 1/4, 1/6, ..., 1/2n} satisfy r < s, then r < k/m < (k+1)/m < s for some integer k.at n=22A024835
- a(n) = least m such that if r and s in {1/1, 1/2, 1/3, ..., 1/n} satisfy r < s, then r < k/m < (k+3)/m < s for some integer k.at n=21A024843
- a(n) = (d(n) - r(n))/5, where d = A026037 and r is the periodic sequence with fundamental period (1,2,0,2,0).at n=27A026039