231440209 has 24 divisors (see below), whose sum is σ = 313113920. Its totient is φ = 166462560.

The previous prime is 231440207. The next prime is 231440219. The reversal of 231440209 is 902044132.

It is not a de Polignac number, because 231440209 - 2¹ = 231440207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (231440201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 502 + ... + 21520.

Almost surely, 2^231440209 is an apocalyptic number.

It is an amenable number.

231440209 is a deficient number, since it is larger than the sum of its proper divisors (81673711).

231440209 is a wasteful number, since it uses less digits than its factorization.

231440209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21061 (or 21050 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 231440209 is about 15213.1590736441. The cubic root of 231440209 is about 613.9687558152.

The spelling of 231440209 in words is "two hundred thirty-one million, four hundred forty thousand, two hundred nine".