6211
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 6212
- Proper Divisor Sum (Aliquot Sum)
- 1
- 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
- 6210
- Möbius Function
- -1
- Radical
- 6211
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
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
- 155
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 808
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Artiads: the primes p == 1 (mod 5) for which Fibonacci((p-1)/5) is divisible by p.at n=39A001583
- Cuban primes: primes which are the difference of two consecutive cubes.at n=23A002407
- Hex (or centered hexagonal) numbers: 3*n*(n+1)+1 (crystal ball sequence for hexagonal lattice).at n=45A003215
- Values of k at which the period of the continued fraction for sqrt(k) sets a new record.at n=41A013645
- Primes that are palindromic in base 2 (but written here in base 10).at n=24A016041
- Primes that remain prime through 3 iterations of function f(x) = 4x + 3.at n=19A023281
- Primes that remain prime through 4 iterations of function f(x) = 4x + 3.at n=2A023311
- Arrange digits of squares in descending order.at n=46A028908
- Numbers k that divide the (left) concatenation of all numbers <= k written in base 7 (most significant digit on left).at n=9A029476
- 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 77.at n=22A031575
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 70 ones.at n=2A031838
- Lucky numbers with size of gaps equal to 16 (upper terms).at n=19A031899
- Lucky numbers with size of gaps equal to 18 (lower terms).at n=37A031900
- Numbers ending with '1' that are the difference of two positive cubes.at n=27A038856
- Primes p such that x^23 = 2 has no solution mod p.at n=38A040984
- Primes with first digit 6.at n=42A045712
- Discriminants of imaginary quadratic fields with class number 15 (negated).at n=26A046012
- Primes from products of split even-digit primes.at n=26A053008
- First member of a prime triple in a 2p-1 progression.at n=31A057326
- First member of a prime quadruple in a 2p-1 progression.at n=4A057327