7905
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
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 13824
- Proper Divisor Sum (Aliquot Sum)
- 5919
- 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
- 3840
- Möbius Function
- 1
- Radical
- 7905
- 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
- 189
- 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
- 4-dimensional analog of centered polygonal numbers: a(n) = n(n+1)*(n^2+n+4)/12.at n=17A006007
- Coefficient of x^4 in (1-x-x^2)^(-n).at n=16A006504
- Numbers whose sum of divisors is a cube.at n=41A020477
- Number of partitions of n into parts of 17 kinds.at n=4A023015
- Number of partitions satisfying 0 < cn(2,5) + cn(3,5).at n=32A039897
- Numerators of continued fraction convergents to sqrt(454).at n=5A041864
- Denominators of continued fraction convergents to sqrt(609).at n=9A042169
- a(n) = period of x^n + x + 1 over GF(2), i.e., the smallest integer m>0 such that x^n + x + 1 divides x^m + 1 over GF(2).at n=12A046932
- Number of bracelets of length n using exactly five different colored beads.at n=7A056345
- Number of primitive (period n) bracelets using exactly five different colored beads.at n=7A056351
- Sum of divisors of twice square numbers.at n=39A065765
- An interleaved sequence of pyramidal and polygonal numbers.at n=33A081283
- Cupolar numbers: a(n) = (n+1)*(5*n^2 + 7*n + 3)/3.at n=16A096000
- Primitive elements of A119432.at n=14A119433
- Number of trisubstituted alkanes C_n H_{2n-1} X_2 Y with n carbon atoms.at n=9A135142
- a(n) = n*(8*n+7).at n=31A139278
- Second bisection of A061041: a(n) = A061041(2n+1) = (2*n+1)*(2*n+9).at n=42A145923
- 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, 0, 0), (0, -1, 0), (0, 0, 1), (0, 1, -1), (1, 1, 0)}.at n=7A150539
- Odd squarefree numbers n such that the cyclotomic polynomial Phi(n,x) has height 4.at n=37A152942
- The non-repetitive Kaprekar binary numbers in decimal.at n=29A163205