16381
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 16382
- 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
- 16380
- Möbius Function
- -1
- Radical
- 16381
- 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
- 159
- 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
- 1900
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Appears in sequences
- Denominators of worst case for Engel expansion.at n=38A006540
- Largest prime <= 2^n.at n=13A014234
- 2^2^2^ ... 2^w (with n 2's), where w = 1.92878... = A086238.at n=3A016104
- Primes that remain prime through 3 iterations of function f(x) = 2x + 9.at n=31A023276
- Primes that remain prime through 4 iterations of function f(x) = 2x + 9.at n=13A023306
- Primes of the form j^2 + (j+1)^2.at n=32A027862
- Primes of form k^2 - 3.at n=23A028874
- Numbers k such that the period of the continued fraction for sqrt(k) contains exactly 88 ones.at n=16A031856
- a(n) = prime(100*n).at n=18A031921
- Base-5 digits are, in order, the first n terms of the periodic sequence with initial period 1,0,1.at n=6A033123
- a(n) = 2^n - 3.at n=14A036563
- Sums of 5 distinct powers of 5.at n=8A038477
- Maximum cardinality of finite D0L sequence over an alphabet with n symbols.at n=39A039952
- Smallest denominator d such that the Sylvester expansion of n/d has n terms.at n=14A048860
- Primes of the form 2^k - 3.at n=7A050415
- Primes -p+2^n with smallest p prime, arising in A057674.at n=13A057674
- New record highs reached in A060030.at n=25A060482
- a(n) = (prime(n)^2 + 1)/2.at n=40A066885
- Prime hypotenuses of Pythagorean triangles with a prime leg.at n=12A067756
- Primes p such that p+3 == 0 (mod phi(p+3)).at n=8A067932