204640009 has 4 divisors (see below), whose sum is σ = 233874304. Its totient is φ = 175405716.

The previous prime is 204640001. The next prime is 204640087. The reversal of 204640009 is 900046402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 204640009 - 2³ = 204640001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204640001) 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, 14617137 + ... + 14617150.

It is an arithmetic number, because the mean of its divisors is an integer number (58468576).

Almost surely, 2^204640009 is an apocalyptic number.

It is an amenable number.

204640009 is a deficient number, since it is larger than the sum of its proper divisors (29234295).

204640009 is an equidigital number, since it uses as much as digits as its factorization.

204640009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29234294.

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 204640009 is about 14305.2441083681. The cubic root of 204640009 is about 589.2915071173.

The spelling of 204640009 in words is "two hundred four million, six hundred forty thousand, nine".