231020221 has 16 divisors (see below), whose sum is σ = 248472000. Its totient is φ = 214144128.

The previous prime is 231020197. The next prime is 231020233. The reversal of 231020221 is 122020132.

It is a cyclic number.

It is not a de Polignac number, because 231020221 - 2⁵ = 231020189 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 (231020821) 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, 219705 + ... + 220753.

It is an arithmetic number, because the mean of its divisors is an integer number (15529500).

Almost surely, 2^231020221 is an apocalyptic number.

It is an amenable number.

231020221 is a deficient number, since it is larger than the sum of its proper divisors (17451779).

231020221 is a wasteful number, since it uses less digits than its factorization.

231020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1308.

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 231020221 is about 15199.3493610746. The cubic root of 231020221 is about 613.5971470310.

Adding to 231020221 its reverse (122020132), we get a palindrome (353040353).

The spelling of 231020221 in words is "two hundred thirty-one million, twenty thousand, two hundred twenty-one".