204657616881 has 9 divisors (see below), whose sum is σ = 295618518091. Its totient is φ = 136437506472.

The previous prime is 204657616873. The next prime is 204657616901. The reversal of 204657616881 is 188616756402.

The square root of 204657616881 is 452391.

It is a perfect power (a square), and thus also a powerful number.

204657616881 is a `hidden beast` number, since 2 + 0 + 4 + 6 + 576 + 1 + 68 + 8 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 34323120225 + 170334496656 = 185265^2 + 412716^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 204657616881 - 2³ = 204657616873 is a prime.

It is a super-2 number, since 2×204657616881² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (204657616081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1281775 + ... + 1432571.

Almost surely, 2^204657616881 is an apocalyptic number.

204657616881 is the 452391-st square number.

204657616881 is the 226196-th centered octagonal number.

It is an amenable number.

204657616881 is a deficient number, since it is larger than the sum of its proper divisors (90960901210).

204657616881 is an frugal number, since it uses more digits than its factorization.

204657616881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301600 (or 150800 counting only the distinct ones).

The product of its (nonzero) digits is 3870720, while the sum is 54.

The spelling of 204657616881 in words is "two hundred four billion, six hundred fifty-seven million, six hundred sixteen thousand, eight hundred eighty-one".