205311390769 has 9 divisors (see below), whose sum is σ = 207262120737. Its totient is φ = 203378863824.

The previous prime is 205311390743. The next prime is 205311390773. The reversal of 205311390769 is 967093113502.

The square root of 205311390769 is 453113.

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

205311390769 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 5065880625 + 200245510144 = 71175^2 + 447488^2 .

It is not a de Polignac number, because 205311390769 - 2⁵ = 205311390737 is a prime.

It is a super-2 number, since 2×205311390769² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205311397769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 49387239 + ... + 49391395.

Almost surely, 2^205311390769 is an apocalyptic number.

205311390769 is the 453113-rd square number.

205311390769 is the 226557-th centered octagonal number.

It is an amenable number.

205311390769 is a deficient number, since it is larger than the sum of its proper divisors (1950729968).

205311390769 is an frugal number, since it uses more digits than its factorization.

205311390769 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8532 (or 4266 counting only the distinct ones).

The product of its (nonzero) digits is 306180, while the sum is 46.

The spelling of 205311390769 in words is "two hundred five billion, three hundred eleven million, three hundred ninety thousand, seven hundred sixty-nine".