205390697 has 4 divisors (see below), whose sum is σ = 206699076. Its totient is φ = 204082320.

The previous prime is 205390693. The next prime is 205390727. The reversal of 205390697 is 796093502.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 48038761 + 157351936 = 6931^2 + 12544^2 .

It is a cyclic number.

It is not a de Polignac number, because 205390697 - 2² = 205390693 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205390693) 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, 653954 + ... + 654267.

It is an arithmetic number, because the mean of its divisors is an integer number (51674769).

Almost surely, 2^205390697 is an apocalyptic number.

It is an amenable number.

205390697 is a deficient number, since it is larger than the sum of its proper divisors (1308379).

205390697 is a wasteful number, since it uses less digits than its factorization.

205390697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1308378.

The product of its (nonzero) digits is 102060, while the sum is 41.

The square root of 205390697 is about 14331.4582998382. The cubic root of 205390697 is about 590.0112005917.

The spelling of 205390697 in words is "two hundred five million, three hundred ninety thousand, six hundred ninety-seven".