7291
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7632
- Proper Divisor Sum (Aliquot Sum)
- 341
- 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
- 6952
- Möbius Function
- 1
- Radical
- 7291
- 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
- 163
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 82.at n=14A020421
- Odd 9-gonal (or enneagonal) numbers.at n=23A028991
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 36 ones.at n=34A031804
- Sums of distinct powers of 9.at n=25A033046
- Positive numbers having the same set of digits in base 2 and base 9.at n=21A037414
- Sums of 3 distinct powers of 9.at n=7A038488
- Numbers k such that k^8 == 1 (mod 9^3).at n=20A056084
- Sum of terms in periodic part of continued fraction expansion of square root of A051451(n), i.e., sqrt(lcm(1..x)) where x is a prime power from A000961.at n=11A077638
- This table shows the coefficients of combinatorial formulas needed for generating the sequential sums of p-th powers of triangular numbers. The p-th row (p>=1) contains a(i,p) for i=1 to 2*p-1, where a(i,p) satisfies Sum_{i=1..n} C(i+1,2)^p = 3 * C(n+2,3) * Sum_{i=1..2*p-1} a(i,p) * C(n-1,i-1)/(i+2).at n=27A087127
- Numbers n such that abs ( (sum_m (m=1..n) d(m)) / n - log(n) - 2*gamma + 1) is a decreasing sequence, where d(m) is the number of divisors A000005(m) and gamma is Euler's constant A001620.at n=19A089084
- Poincaré series [or Poincare series] (or Molien series) for a certain four-fold wreath product P_4.at n=42A091434
- a(n) = 3*n^2 + 27*n + 1.at n=44A110831
- A transform of the central binomial coefficients A001405.at n=15A113409
- a(2*n+1) = 5*a(n), a(2*n+2) = 6*a(n) + a(n-1).at n=42A116553
- Number of isomorphism classes of linking pairings on finite Abelian 2-groups of fixed order 2^n.at n=18A122555
- a(n) = 3*A146085(n) - 2.at n=36A146091
- Triangle defined by T(n,k) = T(n-1,k-1) + Sum_{j=k..n-2} T(n-1,j)*2^j*T(j,k-1) for n>k>0 with T(n,n)=T(n,0)=1, read by rows.at n=29A152795
- Column 1 of triangle A152795.at n=6A152796
- a(n) = 10*n^2 + 1.at n=27A158187
- a(n) = 729*n + 1.at n=9A158397