199643 has 4 divisors (see below), whose sum is σ = 200928. Its totient is φ = 198360.

The previous prime is 199637. The next prime is 199657. The reversal of 199643 is 346991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 346991 = 53 ⋅6547.

It is a cyclic number.

It is not a de Polignac number, because 199643 - 2¹⁴ = 183259 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (199603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 371 + ... + 732.

It is an arithmetic number, because the mean of its divisors is an integer number (50232).

2¹⁹⁹⁶⁴³ is an apocalyptic number.

199643 is a deficient number, since it is larger than the sum of its proper divisors (1285).

199643 is a wasteful number, since it uses less digits than its factorization.

199643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1284.

The product of its digits is 5832, while the sum is 32.

The square root of 199643 is about 446.8142790914. The cubic root of 199643 is about 58.4455382291.

The spelling of 199643 in words is "one hundred ninety-nine thousand, six hundred forty-three".