231057509 has 4 divisors (see below), whose sum is σ = 236693100. Its totient is φ = 225421920.

The previous prime is 231057503. The next prime is 231057551. The reversal of 231057509 is 905750132.

231057509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 67601284 + 163456225 = 8222^2 + 12785^2 .

It is a cyclic number.

It is not a de Polignac number, because 231057509 - 2¹² = 231053413 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231057503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2817734 + ... + 2817815.

It is an arithmetic number, because the mean of its divisors is an integer number (59173275).

Almost surely, 2^231057509 is an apocalyptic number.

It is an amenable number.

231057509 is a deficient number, since it is larger than the sum of its proper divisors (5635591).

231057509 is an equidigital number, since it uses as much as digits as its factorization.

231057509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5635590.

The product of its (nonzero) digits is 9450, while the sum is 32.

The square root of 231057509 is about 15200.5759430358. The cubic root of 231057509 is about 613.6301579646.

The spelling of 231057509 in words is "two hundred thirty-one million, fifty-seven thousand, five hundred nine".