6409
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 7560
- Proper Divisor Sum (Aliquot Sum)
- 1151
- 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
- 5376
- Möbius Function
- -1
- Radical
- 6409
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 124
- 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
- Number of set-like atomic species of degree n.at n=57A007650
- Pseudoprimes to base 30.at n=35A020158
- Pseudoprimes to base 59.at n=30A020187
- Pseudoprimes to base 70.at n=30A020198
- Pseudoprimes to base 86.at n=31A020214
- Numbers k such that the continued fraction for sqrt(k) has period 15.at n=30A020354
- a(n) = n*(19*n - 1)/2.at n=26A022276
- Fibonacci sequence beginning 0, 17.at n=14A022351
- a(n) = 1^2 + prime(1)^2 + prime(2)^2 + ... + prime(n)^2.at n=13A024525
- Numbers that are the sum of 2 nonzero squares in exactly 4 ways.at n=32A025287
- Numbers that are the sum of 2 nonzero squares in 4 or more ways.at n=33A025295
- Numbers that are the sum of 2 distinct nonzero squares in exactly 4 ways.at n=32A025305
- Numbers that are the sum of 2 distinct nonzero squares in 4 or more ways.at n=33A025314
- Quasi-Carmichael numbers to base 9: squarefree composites n such that (n,2*3*5*7) = 1 and prime p|n ==> p-9|n-9.at n=1A029554
- Size of lexicographic code of length n, Hamming distance 6 and weight 6.at n=40A031504
- Numbers whose set of base-8 digits is {1,4}.at n=42A032820
- Composite numbers k, not a power of 2, such that the E(k) == 1 (mod k), where E(k) is the k-th Euler number (A000364).at n=23A035163
- a(1) = 4; a(n) is smallest number >= a(n-1) such that the juxtaposition a(1)a(2)...a(n) is a prime.at n=46A046254
- a(n) = Sum_{k=1..floor((n+1)/2)} T(n,2k-1), array T as in A049777.at n=32A049778
- House numbers: a(n) = (n+1)^3 + Sum_{i=1..n} i^2.at n=16A051662