231423991 has 2 divisors, whose sum is σ = 231423992. Its totient is φ = 231423990.

The previous prime is 231423989. The next prime is 231424007. The reversal of 231423991 is 199324132.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 231423991 - 2¹ = 231423989 is a prime.

It is a super-2 number, since 2×231423991² = 107114127220736162, which contains 22 as substring.

Together with 231423989, 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 (231423931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115711995 + 115711996.

It is an arithmetic number, because the mean of its divisors is an integer number (115711996).

Almost surely, 2^231423991 is an apocalyptic number.

231423991 is a deficient number, since it is larger than the sum of its proper divisors (1).

231423991 is an equidigital number, since it uses as much as digits as its factorization.

231423991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11664, while the sum is 34.

The square root of 231423991 is about 15212.6260389191. The cubic root of 231423991 is about 613.9544143460.

The spelling of 231423991 in words is "two hundred thirty-one million, four hundred twenty-three thousand, nine hundred ninety-one".