6891
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 9192
- Proper Divisor Sum (Aliquot Sum)
- 2301
- 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
- 4592
- Möbius Function
- 1
- Radical
- 6891
- 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
- 150
- 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
- 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 83.at n=0A031581
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 83.at n=0A031761
- Numbers whose base-4 representation contains exactly four 2's and two 3's.at n=18A045155
- Numbers k such that 2*9^k + 1 is prime.at n=19A056802
- Number of 3 X 3 determinants with elements from {0,...,n} and having the value zero.at n=2A059976
- p^2 + 2 where p is a prime.at n=22A061725
- Dimension of the space of weight n cuspidal newforms for Gamma_1( 71 ).at n=33A063344
- a(n) = 10*n^2 + 5*n + 1.at n=26A080860
- Convolution of A000203 with partition function (A000041) of positive integers.at n=16A086732
- Number of compositions of n+2 having exactly two parts equal to 1.at n=15A105423
- Smaller of two consecutive lucky numbers with the same digital sum.at n=27A118566
- Semiprimes that are semiprimes turned upside-down.at n=43A119738
- Number of bicyclic skeletons with n carbon atoms and the parameter 'alpha' having the value of 1. See the paper by Hendrickson and Parks for details.at n=8A125670
- A Moessner triangle using (1, 2, 1, 2, 1, 2, ...).at n=41A125751
- Terms in A061725 that are of form 3*prime.at n=10A133395
- Linear recurrence a(n) = a(n-3) + 2a(n-5), starting from all-one initial conditions.at n=36A133683
- Concatenation of even n and odd n-th nonprime.at n=11A155492
- Sum of all parts of the partitions of n, minus sigma(n).at n=17A162329
- Number of binary strings of length n with no substrings equal to 0001, 0110, or 0111.at n=24A164476
- a(n) = 4*n*(n+1) + 3.at n=41A164897