231221231 has 4 divisors (see below), whose sum is σ = 241274352. Its totient is φ = 221168112.

The previous prime is 231221209. The next prime is 231221239. The reversal of 231221231 is 132122132.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 231221231 - 2⁶ = 231221167 is a prime.

It is a super-2 number, since 2×231221231² = 106926515330310722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231221239) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5026526 + ... + 5026571.

It is an arithmetic number, because the mean of its divisors is an integer number (60318588).

Almost surely, 2^231221231 is an apocalyptic number.

231221231 is a deficient number, since it is larger than the sum of its proper divisors (10053121).

231221231 is a wasteful number, since it uses less digits than its factorization.

231221231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10053120.

The product of its digits is 144, while the sum is 17.

The square root of 231221231 is about 15205.9603774310. The cubic root of 231221231 is about 613.7750584521.

Adding to 231221231 its reverse (132122132), we get a palindrome (363343363).

Subtracting from 231221231 its reverse (132122132), we obtain a palindrome (99099099).

The spelling of 231221231 in words is "two hundred thirty-one million, two hundred twenty-one thousand, two hundred thirty-one".