231622221 has 4 divisors (see below), whose sum is σ = 308829632. Its totient is φ = 154414812.

The previous prime is 231622187. The next prime is 231622231. The reversal of 231622221 is 122226132.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 231622221 - 2¹¹ = 231620173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231622231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 38603701 + ... + 38603706.

It is an arithmetic number, because the mean of its divisors is an integer number (77207408).

Almost surely, 2^231622221 is an apocalyptic number.

It is an amenable number.

231622221 is a deficient number, since it is larger than the sum of its proper divisors (77207411).

231622221 is an equidigital number, since it uses as much as digits as its factorization.

231622221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77207410.

The product of its digits is 576, while the sum is 21.

The square root of 231622221 is about 15219.1399559896. The cubic root of 231622221 is about 614.1296618795.

Adding to 231622221 its reverse (122226132), we get a palindrome (353848353).

The spelling of 231622221 in words is "two hundred thirty-one million, six hundred twenty-two thousand, two hundred twenty-one".