231023521 has 4 divisors (see below), whose sum is σ = 231538500. Its totient is φ = 230508544.

The previous prime is 231023519. The next prime is 231023537. The reversal of 231023521 is 125320132.

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 100721296 + 130302225 = 10036^2 + 11415^2 .

It is a cyclic number.

It is not a de Polignac number, because 231023521 - 2¹ = 231023519 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231023021) 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, 256816 + ... + 257713.

It is an arithmetic number, because the mean of its divisors is an integer number (57884625).

Almost surely, 2^231023521 is an apocalyptic number.

It is an amenable number.

231023521 is a deficient number, since it is larger than the sum of its proper divisors (514979).

231023521 is an equidigital number, since it uses as much as digits as its factorization.

231023521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 514978.

The product of its (nonzero) digits is 360, while the sum is 19.

The square root of 231023521 is about 15199.4579179654. The cubic root of 231023521 is about 613.6000686525.

Adding to 231023521 its reverse (125320132), we get a palindrome (356343653).

The spelling of 231023521 in words is "two hundred thirty-one million, twenty-three thousand, five hundred twenty-one".