231445209 has 4 divisors (see below), whose sum is σ = 308593616. Its totient is φ = 154296804.

The previous prime is 231445169. The next prime is 231445217. The reversal of 231445209 is 902544132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-231445209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (231445009) 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, 38574199 + ... + 38574204.

It is an arithmetic number, because the mean of its divisors is an integer number (77148404).

Almost surely, 2^231445209 is an apocalyptic number.

It is an amenable number.

231445209 is a deficient number, since it is larger than the sum of its proper divisors (77148407).

231445209 is an equidigital number, since it uses as much as digits as its factorization.

231445209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77148406.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 231445209 is about 15213.3234041744. The cubic root of 231445209 is about 613.9731771467.

The spelling of 231445209 in words is "two hundred thirty-one million, four hundred forty-five thousand, two hundred nine".