7405
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 16
- Digital Root
- 7
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 8892
- Proper Divisor Sum (Aliquot Sum)
- 1487
- 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
- 5920
- Möbius Function
- 1
- Radical
- 7405
- 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
- a(n) = floor(n*phi^12), where phi is the golden ratio, A001622.at n=23A004927
- Number of restricted 3 X 3 matrices with row and column sums n.at n=41A005045
- a(n) = floor( n*(n-1)*(n-2)/25 ).at n=58A011907
- Lucky numbers with size of gaps equal to 14 (lower terms).at n=38A031896
- Denominators of continued fraction convergents to sqrt(554).at n=10A042061
- Discriminants of real quadratic fields with class number 2 and related continued fraction period length of 8.at n=36A051973
- Numbers k such that 7*2^k + 5 is prime.at n=18A058595
- Number of strongly unimodal partitions of n (strongly unimodal means strictly increasing then strictly decreasing).at n=30A059618
- Average of squares of successive primes: a(n) = (prime(n+1)^2 + prime(n)^2)/2, with n >= 2.at n=21A075892
- a(n) = a(n-1) + a(n-4); first four terms are 0,1,2,3.at n=28A078467
- Least k such that the distance from k^2 to closest prime = n or zero if no k exists.at n=51A079666
- C(n-3,3)+C(n-7,7)+...+C(n-(4*floor((n-4)/4)+3),4*floor((n-4)/4)+3).at n=22A101552
- Numbers k such that 7*10^k + 5*R_k + 4 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=8A103062
- Number of permutations which avoid the patterns 1324 and (2143 with Bruhat restriction {2<->3}). Also the number of permutations whose graphs are acyclic.at n=7A111053
- Expansion of x*(1 + 3*x)/(1 - 2*x - 25*x^2).at n=5A123008
- Numbers k such that binomial(3k, k) + 1 is prime.at n=19A125221
- 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, -1), (0, 0, 1), (1, -1, 0), (1, 0, 1)}.at n=8A149885
- 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, 1), (-1, 1, -1), (0, 0, 1), (1, -1, 0), (1, 0, 1)}.at n=8A149886
- a(n) = 529*n - 1.at n=13A158365
- a(n) = 14*n^2 - 1.at n=22A158485