206643 has 4 divisors (see below), whose sum is σ = 275528. Its totient is φ = 137760.

The previous prime is 206641. The next prime is 206651. The reversal of 206643 is 346602.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 206643 - 2¹ = 206641 is a prime.

It is a D-number.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is not an unprimeable number, because it can be changed into a prime (206641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34438 + ... + 34443.

It is an arithmetic number, because the mean of its divisors is an integer number (68882).

2²⁰⁶⁶⁴³ is an apocalyptic number.

206643 is a deficient number, since it is larger than the sum of its proper divisors (68885).

206643 is an equidigital number, since it uses as much as digits as its factorization.

206643 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68884.

The product of its (nonzero) digits is 864, while the sum is 21.

The square root of 206643 is about 454.5800259580. The cubic root of 206643 is about 59.1207905529.

The spelling of 206643 in words is "two hundred six thousand, six hundred forty-three".