204523666404661 has 4 divisors (see below), whose sum is σ = 206435102539392. Its totient is φ = 202612230269932.

The previous prime is 204523666404653. The next prime is 204523666404727. The reversal of 204523666404661 is 166404666325402.

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 204523666404661 - 2³ = 204523666404653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204523666404061) 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, 955718067205 + ... + 955718067418.

It is an arithmetic number, because the mean of its divisors is an integer number (51608775634848).

Almost surely, 2^{204523666404661} is an apocalyptic number.

It is an amenable number.

204523666404661 is a deficient number, since it is larger than the sum of its proper divisors (1911436134731).

204523666404661 is a wasteful number, since it uses less digits than its factorization.

204523666404661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1911436134730.

The product of its (nonzero) digits is 29859840, while the sum is 55.

The spelling of 204523666404661 in words is "two hundred four trillion, five hundred twenty-three billion, six hundred sixty-six million, four hundred four thousand, six hundred sixty-one".