7409
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 7680
- Proper Divisor Sum (Aliquot Sum)
- 271
- 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
- 7140
- Möbius Function
- 1
- Radical
- 7409
- 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
- 132
- 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 k divides the (left) concatenation of all numbers <= k written in base 12 (most significant digit on right and removing all least significant zeros before concatenation).at n=6A029529
- Number of partitions of n with equal nonzero number of parts congruent to each of 1 and 2 (mod 4).at n=45A035549
- a(n) = T(4,n), array T given by A048505.at n=7A048509
- a(n) = Sum_{a(k): k=0,1,2,...,n-4,n-2,n-1}; a(n-3) is not a summand; initial terms are 1,1,3.at n=15A049866
- Average of terms of n-th row of A077321.at n=33A077325
- Expansion of psi(x^2) / f(-x) in powers of x where psi(), f() are Ramanujan theta functions.at n=28A098613
- a(n) = a(n-1) + 2*a(n-2) + a(n-3) - a(n-4).at n=12A101400
- Numbers n such that the sum of the digits of the n-th Fibonacci number written in bases 2, 3, 5 and 7 is prime.at n=22A111064
- Numbers n such that f(n), f(n+1) and f(n+2) are prime, f(m)=72*m^2+7.at n=13A121089
- Conjectured lower bound for the number of spheres of radius 1 that can be packed in a sphere of radius n.at n=20A121346
- Column 3 of triangle A128545; a(n) is the coefficient of q^(3n+9) in the central q-binomial coefficient [2n+6,n+3].at n=9A128553
- 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, 0, 0), (0, -1, 0), (0, 0, 1), (1, 1, -1)}.at n=9A148451
- 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, 1, -1), (1, 0, 0), (1, 0, 1)}.at n=7A150430
- Numerators of the Inverse Akiyama-Tanigawa transform of the aerated even-indexed Bernoulli numbers 1, 0, 1/6, 0, -1/30, 0, 1/42, ...at n=8A177427
- Numbers that are 5-digit palindromes in at least two bases.at n=6A180454
- Numerator of H(n+4) - H(n), where H(n) = Sum_{k=1..n} 1/k.at n=13A189642
- Fibonacci sequence beginning 14, 11.at n=14A206605
- Number of partitions p of n such that (number of numbers in p of form 3k) > (number of numbers in p of form 3k+1).at n=40A241745
- Composite numbers k such that sigma(k + sigma(k)) = 2*sigma(k).at n=17A246858
- Palindromic numbers in bases 6 and 8 written in base 10.at n=11A259384