31231213130221 has 16 divisors (see below), whose sum is σ = 33822971273728. Its totient is φ = 28666539316800.

The previous prime is 31231213130197. The next prime is 31231213130237. The reversal of 31231213130221 is 12203131213213.

It is a cyclic number.

It is not a de Polignac number, because 31231213130221 - 2⁹ = 31231213129709 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31231213130281) 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, 21972670 + ... + 23350816.

It is an arithmetic number, because the mean of its divisors is an integer number (2113935704608).

Almost surely, 2^{31231213130221} is an apocalyptic number.

It is an amenable number.

31231213130221 is a deficient number, since it is larger than the sum of its proper divisors (2591758143507).

31231213130221 is a wasteful number, since it uses less digits than its factorization.

31231213130221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1387972.

The product of its (nonzero) digits is 1296, while the sum is 25.

Adding to 31231213130221 its reverse (12203131213213), we get a palindrome (43434344343434).

The spelling of 31231213130221 in words is "thirty-one trillion, two hundred thirty-one billion, two hundred thirteen million, one hundred thirty thousand, two hundred twenty-one".