6401
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 6612
- Proper Divisor Sum (Aliquot Sum)
- 211
- 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
- 6192
- Möbius Function
- 1
- Radical
- 6401
- 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
- 124
- 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
- Pseudoprimes to base 80.at n=36A020208
- Strong pseudoprimes to base 80.at n=11A020306
- a(n) = A027082(n, 2n-2).at n=8A027089
- a(n) = greatest number in row n of array T given by A027082.at n=10A027102
- Numerators of continued fraction convergents to sqrt(938).at n=7A042814
- Semiprimes whose prime factors, when concatenated, yield a palindrome.at n=40A046451
- a(n) = a(n-3) + a(n-5) with initial values 1,0,0,1,0.at n=57A052920
- a(n) = 4*n^2 + 1.at n=40A053755
- Sum of partial sums of partition numbers (A026905) and partial sums of numbers of partitions into distinct parts (A026906).at n=22A056871
- Numbers k for which 10*2^k + 3 is a prime (giving terms of A068712).at n=42A068713
- Prefixing, suffixing or inserting a 9 in the number anywhere gives a prime.at n=31A069833
- Numbers n such that sopf(phi(n)) = phi(sopf(n)), where sopf(x) = sum of the distinct prime factors of x.at n=21A076531
- Numbers n such that mu(n) + mu(n+1) + mu(n+2) + mu(n+3) + mu(n+4) + mu(n+5) + mu(n+6) = 6.at n=5A082967
- a(n) = 16*n^2 + 1.at n=19A108211
- The number of primes between n and n^3 (with n and n^3 excluded).at n=39A117491
- Composite number of the form 4n^2+1.at n=24A121944
- a(n) = least k such that the remainder when 21^k is divided by k is n.at n=39A128361
- a(n) = Sum_{k <= n/2 } binomial(n-2k, 3k).at n=19A137356
- Semiprimes of the form k^2+1.at n=37A144255
- Semiprimes whose factors are decimal palindromes when concatenated, omitting multiples of primes less than 11.at n=20A144719