231261391 has 2 divisors, whose sum is σ = 231261392. Its totient is φ = 231261390.

The previous prime is 231261367. The next prime is 231261397. The reversal of 231261391 is 193162132.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 231261391 - 2⁷ = 231261263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (231261397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115630695 + 115630696.

It is an arithmetic number, because the mean of its divisors is an integer number (115630696).

Almost surely, 2^231261391 is an apocalyptic number.

231261391 is a deficient number, since it is larger than the sum of its proper divisors (1).

231261391 is an equidigital number, since it uses as much as digits as its factorization.

231261391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1944, while the sum is 28.

The square root of 231261391 is about 15207.2808549063. The cubic root of 231261391 is about 613.8105912032.

The spelling of 231261391 in words is "two hundred thirty-one million, two hundred sixty-one thousand, three hundred ninety-one".