231400391 has 2 divisors, whose sum is σ = 231400392. Its totient is φ = 231400390.

The previous prime is 231400381. The next prime is 231400439. The reversal of 231400391 is 193004132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231400391 - 2²² = 227206087 is a prime.

It is a super-2 number, since 2×231400391² = 107092281909905762, which contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231400321) 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, 115700195 + 115700196.

It is an arithmetic number, because the mean of its divisors is an integer number (115700196).

Almost surely, 2^231400391 is an apocalyptic number.

231400391 is a deficient number, since it is larger than the sum of its proper divisors (1).

231400391 is an equidigital number, since it uses as much as digits as its factorization.

231400391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 23.

The square root of 231400391 is about 15211.8503476730. The cubic root of 231400391 is about 613.9335438265.

The spelling of 231400391 in words is "two hundred thirty-one million, four hundred thousand, three hundred ninety-one".