205140391 has 2 divisors, whose sum is σ = 205140392. Its totient is φ = 205140390.

The previous prime is 205140349. The next prime is 205140421. The reversal of 205140391 is 193041502.

205140391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 205140391 - 2¹¹ = 205138343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (205140301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102570195 + 102570196.

It is an arithmetic number, because the mean of its divisors is an integer number (102570196).

Almost surely, 2^205140391 is an apocalyptic number.

205140391 is a deficient number, since it is larger than the sum of its proper divisors (1).

205140391 is an equidigital number, since it uses as much as digits as its factorization.

205140391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 205140391 is about 14322.7228905680. The cubic root of 205140391 is about 589.7714244328.

Adding to 205140391 its reverse (193041502), we get a palindrome (398181893).

The spelling of 205140391 in words is "two hundred five million, one hundred forty thousand, three hundred ninety-one".