231239993 has 2 divisors, whose sum is σ = 231239994. Its totient is φ = 231239992.

The previous prime is 231239941. The next prime is 231240017. The reversal of 231239993 is 399932132.

231239993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205148329 + 26091664 = 14323^2 + 5108^2 .

It is a cyclic number.

It is not a de Polignac number, because 231239993 - 2⁶ = 231239929 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 231239993.

It is not a weakly prime, because it can be changed into another prime (231239293) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115619996 + 115619997.

It is an arithmetic number, because the mean of its divisors is an integer number (115619997).

Almost surely, 2^231239993 is an apocalyptic number.

It is an amenable number.

231239993 is a deficient number, since it is larger than the sum of its proper divisors (1).

231239993 is an equidigital number, since it uses as much as digits as its factorization.

231239993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78732, while the sum is 41.

The square root of 231239993 is about 15206.5772940527. The cubic root of 231239993 is about 613.7916592001.

It can be divided in two parts, 231239 and 993, that added together give a palindrome (232232).

The spelling of 231239993 in words is "two hundred thirty-one million, two hundred thirty-nine thousand, nine hundred ninety-three".