1731
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 2312
- Proper Divisor Sum (Aliquot Sum)
- 581
- 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
- 1152
- Möbius Function
- 1
- Radical
- 1731
- 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
- 148
- 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
- Pseudo-bricks with n nodes.at n=3A006291
- If a, b in sequence, so is ab+5.at n=25A009304
- Numbers k such that the geometric mean of phi(k) and sigma(k) is an integer.at n=27A011257
- Geometric mean of phi(n) and sigma(n) is an integer, n odd.at n=12A015705
- Smallest odd k>n such that k | n^k + n, or 0 if n=2^m.at n=24A015908
- a(n+1) (n >= 1) is smallest number > a(n) which is the sum of cubes of distinct earlier terms.at n=38A019511
- Nearest integer to Gamma(n + 7/11)/Gamma(7/11).at n=7A020008
- a(n) = floor(Gamma(n + 7/11)/Gamma(7/11)).at n=7A020053
- Place where n-th 1 occurs in A023123.at n=35A022785
- a(n) = n^2 + n + 9.at n=41A027694
- Number of nonisomorphic and nonantiisomorphic reflexive transitive and cotransitive (complement is transitive) relations.at n=10A030270
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 26.at n=20A031524
- Lucky numbers with size of gaps equal to 8 (upper terms).at n=17A031891
- Numbers k such that 147*2^k+1 is prime.at n=20A032423
- Numbers whose set of base-9 digits is {2,3}.at n=21A032809
- Numbers with the property that all pairs of consecutive base-3 digits differ by 1.at n=43A033068
- Fractional part of square root of a(n) starts with 6: first term of runs.at n=39A034112
- a(n) is the smallest number such that the product a(1)a(2)...a(n) falls between a twin prime pair, starting with a(1)=2.at n=47A036014
- a(n) is the number of distinct possible values of d(k), the number of divisors of k, among numbers k whose binary order (A029837) does not exceed n.at n=54A036470
- Number of partitions of n such that cn(1,5) < cn(0,5) = cn(2,5) < cn(3,5) = cn(4,5).at n=76A036861