231309993 has 4 divisors (see below), whose sum is σ = 308413328. Its totient is φ = 154206660.

The previous prime is 231309979. The next prime is 231309997. The reversal of 231309993 is 399903132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 231309993 - 2¹⁴ = 231293609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231309997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38551663 + ... + 38551668.

It is an arithmetic number, because the mean of its divisors is an integer number (77103332).

Almost surely, 2^231309993 is an apocalyptic number.

It is an amenable number.

231309993 is a deficient number, since it is larger than the sum of its proper divisors (77103335).

231309993 is an equidigital number, since it uses as much as digits as its factorization.

231309993 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77103334.

The product of its (nonzero) digits is 39366, while the sum is 39.

The square root of 231309993 is about 15208.8787555165. The cubic root of 231309993 is about 613.8535877631.

The spelling of 231309993 in words is "two hundred thirty-one million, three hundred nine thousand, nine hundred ninety-three".