231809513 has 4 divisors (see below), whose sum is σ = 249641028. Its totient is φ = 213978000.

The previous prime is 231809509. The next prime is 231809521. The reversal of 231809513 is 315908132.

231809513 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 75134224 + 156675289 = 8668^2 + 12517^2 .

It is a cyclic number.

It is not a de Polignac number, because 231809513 - 2² = 231809509 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 231809513.

It is not an unprimeable number, because it can be changed into a prime (231809573) 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, 8915738 + ... + 8915763.

It is an arithmetic number, because the mean of its divisors is an integer number (62410257).

Almost surely, 2^231809513 is an apocalyptic number.

It is an amenable number.

231809513 is a deficient number, since it is larger than the sum of its proper divisors (17831515).

231809513 is a wasteful number, since it uses less digits than its factorization.

231809513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17831514.

The product of its (nonzero) digits is 6480, while the sum is 32.

The square root of 231809513 is about 15225.2918855436. The cubic root of 231809513 is about 614.2951477060.

The spelling of 231809513 in words is "two hundred thirty-one million, eight hundred nine thousand, five hundred thirteen".