231211021221 has 6 divisors (see below), whose sum is σ = 333971475110. Its totient is φ = 154140680808.

The previous prime is 231211021213. The next prime is 231211021243. The reversal of 231211021221 is 122120112132.

231211021221 is a `hidden beast` number, since 2 + 312 + 110 + 21 + 221 = 666.

It can be written as a sum of positive squares in only one way, i.e., 177502958721 + 53708062500 = 421311^2 + 231750^2 .

It is not a de Polignac number, because 231211021221 - 2³ = 231211021213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 231211021194 and 231211021203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231211021021) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12845056726 + ... + 12845056743.

Almost surely, 2^231211021221 is an apocalyptic number.

It is an amenable number.

231211021221 is a deficient number, since it is larger than the sum of its proper divisors (102760453889).

231211021221 is a wasteful number, since it uses less digits than its factorization.

231211021221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25690113475 (or 25690113472 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 231211021221 its reverse (122120112132), we get a palindrome (353331133353).

The spelling of 231211021221 in words is "two hundred thirty-one billion, two hundred eleven million, twenty-one thousand, two hundred twenty-one".