6402
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
- 14112
- Proper Divisor Sum (Aliquot Sum)
- 7710
- 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
- 6402
- 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
- 168
- 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
- Number of points on surface of octahedron; also coordination sequence for cubic lattice: a(0) = 1; for n > 0, a(n) = 4n^2 + 2.at n=40A005899
- Coordination sequence for C_3 lattice: a(n) = 16*n^2 + 2 (n>0), a(0)=1.at n=20A010006
- a(0) = 1, a(n) = 25*n^2 + 2 for n > 0.at n=16A010015
- 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 80.at n=0A031578
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 80.at n=1A031758
- Maximal base 7 run length is 4.at n=27A037991
- Base-5 palindromes that start with 2.at n=38A043007
- Numbers whose base-7 representation contains exactly four 4's.at n=2A043412
- Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2); sequence gives values of u2.at n=19A048190
- Lesser members of g-reduced amicable pairs a < b such that sigma(a) = sigma(b) = a + b + gcd(a,b).at n=26A054573
- Numbers k such that 5*2^k + 3 is prime.at n=42A058586
- Composite numbers k such that sigma(k)*(phi(k) + 2) is a square.at n=16A065655
- a(1)=1, a(n) is the smallest integer > a(n-1) such that the largest element in the simple continued fraction for S(n)=1/a(1)+1/a(2)+...+1/a(n) equals 3n.at n=36A070899
- Diagonal of triangular spiral in A051682.at n=37A081268
- Numbers k such that numerator(Bernoulli(2*k)/(2*k)) is different from numerator(Bernoulli(2*k)/(2*k*(2*k-1))).at n=23A090495
- Number of partitions of n such that there is exactly one part which occurs twice, while all other parts occur only once.at n=48A090858
- a(n) = floor(sqrt(a(n-1)^2 + a(n-2)^2)), a(1)=10, a(2)=30.at n=24A104863
- a(n) = floor(n^sqrt(2*Pi)).at n=32A134887
- Twice octagonal numbers: 2*n*(3*n-2).at n=33A139267
- Numbers k such that prime(1)^1 + prime(2)^2 + ... + prime(k)^k is prime.at n=3A179056