231215666 has 16 divisors (see below), whose sum is σ = 391400640. Its totient is φ = 101473680.

The previous prime is 231215659. The next prime is 231215669. The reversal of 231215666 is 666512132.

231215666 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (231215669) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 180566 + ... + 181841.

It is an arithmetic number, because the mean of its divisors is an integer number (24462540).

Almost surely, 2^231215666 is an apocalyptic number.

231215666 is a deficient number, since it is larger than the sum of its proper divisors (160184974).

231215666 is a wasteful number, since it uses less digits than its factorization.

231215666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362449.

The product of its digits is 12960, while the sum is 32.

The square root of 231215666 is about 15205.7773888743. Note that the first 3 decimals coincide. The cubic root of 231215666 is about 613.7701343287.

Adding to 231215666 its reverse (666512132), we get a palindrome (897727798).

The spelling of 231215666 in words is "two hundred thirty-one million, two hundred fifteen thousand, six hundred sixty-six".