231138666 has 48 divisors (see below), whose sum is σ = 563966208. Its totient is φ = 67780800.

The previous prime is 231138653. The next prime is 231138703. The reversal of 231138666 is 666831132.

231138666 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 231138666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12691 + ... + 24966.

It is an arithmetic number, because the mean of its divisors is an integer number (11749296).

Almost surely, 2^231138666 is an apocalyptic number.

231138666 is an abundant number, since it is smaller than the sum of its proper divisors (332827542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

231138666 is a wasteful number, since it uses less digits than its factorization.

231138666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37707 (or 37704 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 231138666 is about 15203.2452456704. The cubic root of 231138666 is about 613.7019936927.

Adding to 231138666 its reverse (666831132), we get a palindrome (897969798).

The spelling of 231138666 in words is "two hundred thirty-one million, one hundred thirty-eight thousand, six hundred sixty-six".