31212342221 has 4 divisors (see below), whose sum is σ = 31248934332. Its totient is φ = 31175750112.

The previous prime is 31212342173. The next prime is 31212342253. The reversal of 31212342221 is 12224321213.

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 6599125225 + 24613216996 = 81235^2 + 156886^2 .

It is a cyclic number.

It is not a de Polignac number, because 31212342221 - 2³⁰ = 30138600397 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 (31212342521) 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, 18294776 + ... + 18296481.

It is an arithmetic number, because the mean of its divisors is an integer number (7812233583).

Almost surely, 2^31212342221 is an apocalyptic number.

It is an amenable number.

31212342221 is a deficient number, since it is larger than the sum of its proper divisors (36592111).

31212342221 is an equidigital number, since it uses as much as digits as its factorization.

31212342221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36592110.

The product of its digits is 1152, while the sum is 23.

Adding to 31212342221 its reverse (12224321213), we get a palindrome (43436663434).

The spelling of 31212342221 in words is "thirty-one billion, two hundred twelve million, three hundred forty-two thousand, two hundred twenty-one".