231213665 has 16 divisors (see below), whose sum is σ = 287614800. Its totient is φ = 178225152.

The previous prime is 231213659. The next prime is 231213683. The reversal of 231213665 is 566312132.

It can be written as a sum of positive squares in 8 ways, for example, as 19918369 + 211295296 = 4463^2 + 14536^2 .

It is a cyclic number.

It is not a de Polignac number, because 231213665 - 2⁴ = 231213649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84641 + ... + 87329.

It is an arithmetic number, because the mean of its divisors is an integer number (17975925).

Almost surely, 2^231213665 is an apocalyptic number.

It is an amenable number.

231213665 is a deficient number, since it is larger than the sum of its proper divisors (56401135).

231213665 is a wasteful number, since it uses less digits than its factorization.

231213665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3316.

The product of its digits is 6480, while the sum is 29.

The square root of 231213665 is about 15205.7115913725. The cubic root of 231213665 is about 613.7683637486.

Adding to 231213665 its reverse (566312132), we get a palindrome (797525797).

The spelling of 231213665 in words is "two hundred thirty-one million, two hundred thirteen thousand, six hundred sixty-five".