204507666561 has 8 divisors (see below), whose sum is σ = 297465696864. Its totient is φ = 123944040320.

The previous prime is 204507666553. The next prime is 204507666577. The reversal of 204507666561 is 165666705402.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 204507666561 - 2³ = 204507666553 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 204507666561.

It is not an unprimeable number, because it can be changed into a prime (204507666551) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3098600976 + ... + 3098601041.

It is an arithmetic number, because the mean of its divisors is an integer number (37183212108).

Almost surely, 2^204507666561 is an apocalyptic number.

It is an amenable number.

204507666561 is a deficient number, since it is larger than the sum of its proper divisors (92958030303).

204507666561 is a wasteful number, since it uses less digits than its factorization.

204507666561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6197202031.

The product of its (nonzero) digits is 1814400, while the sum is 48.

The spelling of 204507666561 in words is "two hundred four billion, five hundred seven million, six hundred sixty-six thousand, five hundred sixty-one".