231148721 has 2 divisors, whose sum is σ = 231148722. Its totient is φ = 231148720.

The previous prime is 231148717. The next prime is 231148739. The reversal of 231148721 is 127841132.

231148721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 143520400 + 87628321 = 11980^2 + 9361^2 .

It is a cyclic number.

It is not a de Polignac number, because 231148721 - 2² = 231148717 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (231148751) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115574360 + 115574361.

It is an arithmetic number, because the mean of its divisors is an integer number (115574361).

Almost surely, 2^231148721 is an apocalyptic number.

It is an amenable number.

231148721 is a deficient number, since it is larger than the sum of its proper divisors (1).

231148721 is an equidigital number, since it uses as much as digits as its factorization.

231148721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 29.

The square root of 231148721 is about 15203.5759280506. The cubic root of 231148721 is about 613.7108926568.

Adding to 231148721 its reverse (127841132), we get a palindrome (358989853).

The spelling of 231148721 in words is "two hundred thirty-one million, one hundred forty-eight thousand, seven hundred twenty-one".