7239
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 5
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 10240
- Proper Divisor Sum (Aliquot Sum)
- 3001
- 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
- 4536
- Möbius Function
- -1
- Radical
- 7239
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 44
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- 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 that divide s(k), where s(1)=1, s(j)=19*s(j-1)+j.at n=19A014869
- a(n) = floor((3rd elementary symmetric function of 2,3,...,n+3)/(2+3+...+n+3)).at n=17A024178
- a(n) = n^3 + n^2 + n.at n=19A027444
- 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 56.at n=25A031554
- Numbers whose base-5 representation contains exactly three 2's and two 4's.at n=27A045291
- Number of 2-colored generalized Frobenius partitions.at n=14A051136
- Integers n > 7059 such that the 'Reverse and Add!' trajectory of n joins the trajectory of 7059.at n=1A063058
- Numbers n such that nextprime(n^3)-prevprime(n^3) = 4.at n=35A090121
- Largest member of the n-th row of the triangular triangle (A093445).at n=32A093446
- Start with 1013 and repeatedly reverse the digits and add 2 to get the next term.at n=26A120214
- Rectangular table, read by antidiagonals, where the g.f. of row n is Sum_{i>=0} F_i(x)^n / 2^(i+1), where F_0(x)=x, F_{n+1}(x) = F_n(x+x^2), for n>=1.at n=49A122941
- Indices where 2 occurs in A124151.at n=23A124401
- Numbers k such that 1 + Sum_{i=1..k} 2^(2*i-1) is prime.at n=28A127936
- Ceiling(4*Pi*n^2).at n=23A135971
- Ceiling(4/3*Pi*n^3).at n=12A135973
- Expansion of phi(x) / f(-x^4)^2 in powers of x where phi(), f() are Ramanujan theta functions.at n=56A137828
- Expansion of phi(-x) / f(-x^4)^2 in powers of x where phi(), f() are Ramanujan theta functions.at n=56A137830
- a(n) = (7*n^2 + 7*n - 12)/2.at n=44A166146
- Products of 3 distinct primes whose binary expansion is palindromic.at n=34A168355
- Numbers that are the product of two odd numbers x*y such that 2^x (mod y) = 2^y (mod x) = 2.at n=46A176970