7389
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 27
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 10686
- Proper Divisor Sum (Aliquot Sum)
- 3297
- 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
- 4920
- Möbius Function
- 0
- Radical
- 2463
- Omega Function (Ω)
- 3
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 70
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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 100.at n=9A020439
- a(n) = (1/3)*(2 + Sum_{k=0..n} C(3k,k)).at n=6A024719
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 44 ones.at n=23A031812
- a(1) = 1; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=46A033680
- Can express a(n) with the digits of a(n)^2 in order, only adding plus signs.at n=48A038206
- Numbers n such that sigma(n)^2 - phi(n)^2 is a perfect square.at n=25A057654
- Let z(n) be the golden ratio (phi) truncated to n decimal digits; sequence gives maximum element in the continued fraction for z(n).at n=56A081836
- Integers m such that the base-10 digit concatenation 2//m//3//m//5//m...//prime(49)//m//prime(50) is prime.at n=16A084048
- Antidiagonal sums of triangle A107105: a(n) = Sum_{k=0..n} A107105(n-k,k), where A107105(n,k) = C(n,k)*(C(n,k) + 1)/2.at n=12A107597
- Triangle T(n,k), read by rows n>=0 with terms k=1..3^n, where row n lists the coefficients in the n-th iteration of (x+x^2+x^3).at n=28A166880
- Triangle T(n,m) = coefficient of x^n in expansion of (1/2-1/2*(1-8*x)^1/4)^m = sum(n>=m, T(n,m) x^n), n>=1, m>=1.at n=31A202039
- Triangle read by rows. T(n, k) = coefficient of x^n in the Taylor expansion of [((1 - x - 2*x^2 - sqrt(1 - 2*x - 3*x^2))/(2*x^2))]^k.at n=47A202710
- Triangle of coefficients of polynomials v(n,x) jointly generated with A210201; see the Formula section.at n=49A210202
- Number of (n+1)X(n+1) -10..10 symmetric matrices with every 2X2 subblock having sum zero and one, two or three distinct values.at n=4A211817
- G.f. C(x) satisfies: C(x) = x + 3*A(x)*B(x), where A(x) = x + B(x)*C(x) and B(x) = x + 2*A(x)*C(x).at n=6A229813
- Number of partitions of n where the frequencies alternate in parity.at n=49A242984
- Binary representation of base-(i-1) expansion of -n: replace i-1 with 2 in base-(i-1) expansion of -n.at n=41A256441
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 633", based on the 5-celled von Neumann neighborhood.at n=44A273299
- Numbers k such that (94*10^k - 7) / 3 is prime.at n=22A278336
- Odd numbers k > 1 such that k == 1 (mod 4), Product_{n>=1} (a(n)-1)/(a(n)+1) = Pi/4, and Limit_{n->oo} a(n+1)/a(n) = 3, where a(1) = 13 (see comments).at n=6A317986