16823
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
- 4
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 16824
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 16822
- Möbius Function
- -1
- Radical
- 16823
- 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
- 66
- 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
- yes
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 1941
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Number of chiral pairs of polyominoes with n cells.at n=11A030228
- Number of planted planar trees (n+1 nodes) where any 2 subtrees extending from the same node have a different number of nodes.at n=12A032009
- Restricted left truncatable (Henry VIII) primes.at n=9A055521
- Smallest prime equal to the sum of 2n+1 consecutive primes.at n=40A070934
- Smallest odd prime that is the sum of 2n+1 consecutive primes.at n=40A082244
- Primes which remain prime after one and after two applications of the rotate-and-add operation of A086002.at n=9A086003
- Primes of the form a^5 + b^4 with a>0.at n=10A100274
- Indices of primes in sequence defined by A(0) = 81, A(n) = 10*A(n-1) + 61 for n > 0.at n=8A101076
- Retrograde trajectory of 13 under map n -> A132948(n).at n=43A132947
- Primes congruent to 44 mod 47.at n=36A142395
- Primes congruent to 16 mod 49.at n=41A142427
- Primes congruent to 22 mod 53.at n=34A142552
- Primes congruent to 8 mod 59.at n=32A142735
- Primes congruent to 48 mod 61.at n=30A142846
- a(n) = (p(n)*p(n+2) - 3*p(n+1))/2, where p(n) is the n-th odd prime.at n=39A152529
- a(n) = 20*n^2 + 3.at n=28A167573
- Primes p such that 2*p^3 -+ 3 are also prime.at n=18A174363
- Primes of the form 5n^2 + 3.at n=13A201482
- Minimal number (in decimal representation) with n nonprime substrings in base-7 representation (substrings with leading zeros are considered to be nonprime).at n=17A217107
- Primes of the form 2*n^2 + 50*n + 23.at n=21A217496