204664643 has 4 divisors (see below), whose sum is σ = 204805248. Its totient is φ = 204524040.

The previous prime is 204664631. The next prime is 204664657. The reversal of 204664643 is 346466402.

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

It is a cyclic number.

It is not a de Polignac number, because 204664643 - 2²⁰ = 203616067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204664673) 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, 68096 + ... + 71037.

It is an arithmetic number, because the mean of its divisors is an integer number (51201312).

Almost surely, 2^204664643 is an apocalyptic number.

204664643 is a deficient number, since it is larger than the sum of its proper divisors (140605).

204664643 is a wasteful number, since it uses less digits than its factorization.

204664643 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140604.

The product of its (nonzero) digits is 82944, while the sum is 35.

The square root of 204664643 is about 14306.1050953780. The cubic root of 204664643 is about 589.3151519308.

The spelling of 204664643 in words is "two hundred four million, six hundred sixty-four thousand, six hundred forty-three".