198643 has 4 divisors (see below), whose sum is σ = 199648. Its totient is φ = 197640.

The previous prime is 198641. The next prime is 198647. The reversal of 198643 is 346891.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 198643 - 2¹ = 198641 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is not an unprimeable number, because it can be changed into a prime (198641) 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, 96 + ... + 637.

It is an arithmetic number, because the mean of its divisors is an integer number (49912).

2¹⁹⁸⁶⁴³ is an apocalyptic number.

198643 is a deficient number, since it is larger than the sum of its proper divisors (1005).

198643 is an equidigital number, since it uses as much as digits as its factorization.

198643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1004.

The product of its digits is 5184, while the sum is 31.

The square root of 198643 is about 445.6938411062. The cubic root of 198643 is about 58.3477914276.

It can be divided in two parts, 198 and 643, that added together give a square (841 = 29²).

The spelling of 198643 in words is "one hundred ninety-eight thousand, six hundred forty-three".