231431311 has 2 divisors, whose sum is σ = 231431312. Its totient is φ = 231431310.

The previous prime is 231431309. The next prime is 231431329. The reversal of 231431311 is 113134132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231431311 - 2¹ = 231431309 is a prime.

It is a super-2 number, since 2×231431311² = 107120903422357442, which contains 22 as substring.

Together with 231431309, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231431371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115715655 + 115715656.

It is an arithmetic number, because the mean of its divisors is an integer number (115715656).

Almost surely, 2^231431311 is an apocalyptic number.

231431311 is a deficient number, since it is larger than the sum of its proper divisors (1).

231431311 is an equidigital number, since it uses as much as digits as its factorization.

231431311 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 216, while the sum is 19.

The square root of 231431311 is about 15212.8666266421. The cubic root of 231431311 is about 613.9608874561.

Adding to 231431311 its reverse (113134132), we get a palindrome (344565443).

The spelling of 231431311 in words is "two hundred thirty-one million, four hundred thirty-one thousand, three hundred eleven".