7230
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
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 17424
- Proper Divisor Sum (Aliquot Sum)
- 10194
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 1920
- Möbius Function
- 1
- Radical
- 7230
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 70
- 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
- yes
- Odd
- no
Appears in sequences
- Theta series of direct sum of 5 copies of hexagonal lattice.at n=4A008656
- a(n) = floor(n*(n-1)*(n-2)/7).at n=38A011889
- Start with 1, apply 1->12, 21->21, 22->21, 2->2 (for final 2); a(n) = length of n-th term.at n=27A013950
- a(n) = n^2 + (n+1)^2 + (n+2)^2 + (n+3)^2.at n=41A027575
- Sums of five consecutive squares: a(n) = n^2 + (n+1)^2 + (n+2)^2 + (n+3)^2 + (n+4)^2.at n=36A027578
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 34.at n=4A031712
- Both sum of n+1 consecutive squares and sum of the immediately following n consecutive squares.at n=4A059255
- Numbers that are sums of 2 or more consecutive squares in more than 1 way.at n=13A062681
- Squarefree n such that the elliptic curve n*y^2 = x^3 - x arising in the "congruent number" problem has rank 3.at n=9A062693
- Numbers k such that usigma(k) is a square and sets a new record for such squares.at n=16A064443
- a(n+4) = a(n+1) - a(n), a(0) = 1, a(1) = -4, a(2) = 0, a(3) = 1.at n=50A110064
- Numbers that are the sum of one or more consecutive squares in more than one way.at n=17A130052
- a(n) = n*(8*n+1).at n=30A139275
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, 0), (0, 0, -1), (0, 1, 1), (1, 0, 1)}.at n=7A150483
- a(n) = 25*n^2 + 5.at n=16A158445
- a(n) = Sum_{i+j=n, i,j >= 1} tau(i)*sigma(j), where tau() = A000005(), sigma() = A000203().at n=50A191831
- Area of the Robbins pentagons.at n=36A228517
- Numbers n for which n' + n and n' - n are both prime, n' being the arithmetic derivative of n.at n=20A229272
- Number of partitions of n, where the difference between the number of odd parts and the number of even parts is 5.at n=42A240014
- a(n) gives one fourth of the even leg of the second of the two Pythagorean triangles with hypotenuse A080109(n) = A002144(n)^2. The odd leg is given in A253804.at n=23A253805