204605981 has 2 divisors, whose sum is σ = 204605982. Its totient is φ = 204605980.

The previous prime is 204605977. The next prime is 204606037. The reversal of 204605981 is 189506402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 156025081 + 48580900 = 12491^2 + 6970^2 .

It is a cyclic number.

It is not a de Polignac number, because 204605981 - 2² = 204605977 is a prime.

It is a super-2 number, since 2×204605981² = 83727214921944722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204605941) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102302990 + 102302991.

It is an arithmetic number, because the mean of its divisors is an integer number (102302991).

Almost surely, 2^204605981 is an apocalyptic number.

It is an amenable number.

204605981 is a deficient number, since it is larger than the sum of its proper divisors (1).

204605981 is an equidigital number, since it uses as much as digits as its factorization.

204605981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 204605981 is about 14304.0547048730. The cubic root of 204605981 is about 589.2588424019.

The spelling of 204605981 in words is "two hundred four million, six hundred five thousand, nine hundred eighty-one".