205664281 has 3 divisors (see below), whose sum is σ = 205678623. Its totient is φ = 205649940.

The previous prime is 205664273. The next prime is 205664293. The reversal of 205664281 is 182466502.

The square root of 205664281 is 14341.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 3455881 + 202208400 = 1859^2 + 14220^2 .

It is not a de Polignac number, because 205664281 - 2³ = 205664273 is a prime.

It is a super-2 number, since 2×205664281² = 84595592958493922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205664581) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 7171 + ... + 21511.

It is an arithmetic number, because the mean of its divisors is an integer number (68559541).

Almost surely, 2^205664281 is an apocalyptic number.

205664281 is the 14341-st square number.

205664281 is the 7171-st centered octagonal number.

It is an amenable number.

205664281 is a deficient number, since it is larger than the sum of its proper divisors (14342).

205664281 is an frugal number, since it uses more digits than its factorization.

205664281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28682 (or 14341 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 34.

The cubic root of 205664281 is about 590.2730527744.

The spelling of 205664281 in words is "two hundred five million, six hundred sixty-four thousand, two hundred eighty-one".