231131032221 has 16 divisors (see below), whose sum is σ = 312901729920. Its totient is φ = 151729213440.

The previous prime is 231131032217. The next prime is 231131032247. The reversal of 231131032221 is 122230131132.

It is not a de Polignac number, because 231131032221 - 2² = 231131032217 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231131032201) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 498340 + ... + 842973.

It is an arithmetic number, because the mean of its divisors is an integer number (19556358120).

Almost surely, 2^231131032221 is an apocalyptic number.

It is an amenable number.

231131032221 is a deficient number, since it is larger than the sum of its proper divisors (81770697699).

231131032221 is a wasteful number, since it uses less digits than its factorization.

231131032221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342196.

The product of its (nonzero) digits is 432, while the sum is 21.

Adding to 231131032221 its reverse (122230131132), we get a palindrome (353361163353).

The spelling of 231131032221 in words is "two hundred thirty-one billion, one hundred thirty-one million, thirty-two thousand, two hundred twenty-one".