205390761 has 4 divisors (see below), whose sum is σ = 273854352. Its totient is φ = 136927172.

The previous prime is 205390751. The next prime is 205390763. The reversal of 205390761 is 167093502.

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 205390761 - 2⁹ = 205390249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (205390763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34231791 + ... + 34231796.

It is an arithmetic number, because the mean of its divisors is an integer number (68463588).

Almost surely, 2^205390761 is an apocalyptic number.

It is an amenable number.

205390761 is a deficient number, since it is larger than the sum of its proper divisors (68463591).

205390761 is an equidigital number, since it uses as much as digits as its factorization.

205390761 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68463590.

The product of its (nonzero) digits is 11340, while the sum is 33.

The square root of 205390761 is about 14331.4605326882. The cubic root of 205390761 is about 590.0112618745.

The spelling of 205390761 in words is "two hundred five million, three hundred ninety thousand, seven hundred sixty-one".