231667715221 has 4 divisors (see below), whose sum is σ = 231676596844. Its totient is φ = 231658833600.

The previous prime is 231667715207. The next prime is 231667715233. The reversal of 231667715221 is 122517766132.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 89622396900 + 142045318321 = 299370^2 + 376889^2 .

It is a cyclic number.

It is not a de Polignac number, because 231667715221 - 2⁵ = 231667715189 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 (231667715621) 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, 4401570 + ... + 4453891.

It is an arithmetic number, because the mean of its divisors is an integer number (57919149211).

Almost surely, 2^231667715221 is an apocalyptic number.

It is an amenable number.

231667715221 is a deficient number, since it is larger than the sum of its proper divisors (8881623).

231667715221 is an equidigital number, since it uses as much as digits as its factorization.

231667715221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8881622.

The product of its digits is 211680, while the sum is 43.

The spelling of 231667715221 in words is "two hundred thirty-one billion, six hundred sixty-seven million, seven hundred fifteen thousand, two hundred twenty-one".