231548561 has 2 divisors, whose sum is σ = 231548562. Its totient is φ = 231548560.

The previous prime is 231548549. The next prime is 231548609. The reversal of 231548561 is 165845132.

231548561 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., 216648961 + 14899600 = 14719^2 + 3860^2 .

It is a cyclic number.

It is not a de Polignac number, because 231548561 - 2¹⁸ = 231286417 is a prime.

It is a super-2 number, since 2×231548561² = 107229472202341442, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (231548761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 115774280 + 115774281.

It is an arithmetic number, because the mean of its divisors is an integer number (115774281).

Almost surely, 2^231548561 is an apocalyptic number.

It is an amenable number.

231548561 is a deficient number, since it is larger than the sum of its proper divisors (1).

231548561 is an equidigital number, since it uses as much as digits as its factorization.

231548561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28800, while the sum is 35.

The square root of 231548561 is about 15216.7197845002. The cubic root of 231548561 is about 614.0645535795.

The spelling of 231548561 in words is "two hundred thirty-one million, five hundred forty-eight thousand, five hundred sixty-one".