16805
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 20172
- Proper Divisor Sum (Aliquot Sum)
- 3367
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13440
- Möbius Function
- 1
- Radical
- 16805
- 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
- 66
- 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
- Ordered sequence of distinct terms of the form floor(x^i * floor(x^j)), i,j >= 0, where x = sqrt(7).at n=34A022771
- Numbers whose concatenation of prime factors (with multiplicity) is a square.at n=35A038693
- Numbers whose base-7 representation contains exactly four 6's.at n=29A043420
- a(n) = (2^n - 1)^5 - 2.at n=3A098879
- Number of partitions of n such that all parts, with the possible exception of the smallest, appear only once.at n=48A115029
- a(n) = least k such that the remainder when 23^k is divided by k is n.at n=27A128363
- Monotonic ordering of nonnegative differences 7^i-2^j, for 40>=i>=0, j>=0.at n=44A192119
- Number of terms k such that difference between halving and tripling steps in Collatz (3x+1) trajectory of k is n.at n=25A213678
- Positive integers n such that 7^n == 2 (mod n).at n=6A277401
- Value of the n-th Roman number interpreted as Latin alphabetic number.at n=15A285511
- Expansion of 1/(1 - x*Product_{k>=1} (1 + x^k)/(1 - x^k)).at n=10A299108
- a(n) = 2^n + 2*n^2 + 2*n + 1.at n=14A321123