31121331113221 has 4 divisors (see below), whose sum is σ = 31124937719500. Its totient is φ = 31117724506944.

The previous prime is 31121331113161. The next prime is 31121331113233. The reversal of 31121331113221 is 12231113312113.

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 27870111016225 + 3251220096996 = 5279215^2 + 1803114^2 .

It is a cyclic number.

It is not a de Polignac number, because 31121331113221 - 2¹¹ = 31121331111173 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 (31121331114221) 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, 1803290196 + ... + 1803307453.

It is an arithmetic number, because the mean of its divisors is an integer number (7781234429875).

Almost surely, 2^{31121331113221} is an apocalyptic number.

It is an amenable number.

31121331113221 is a deficient number, since it is larger than the sum of its proper divisors (3606606279).

31121331113221 is an equidigital number, since it uses as much as digits as its factorization.

31121331113221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3606606278.

The product of its digits is 648, while the sum is 25.

Adding to 31121331113221 its reverse (12231113312113), we get a palindrome (43352444425334).

The spelling of 31121331113221 in words is "thirty-one trillion, one hundred twenty-one billion, three hundred thirty-one million, one hundred thirteen thousand, two hundred twenty-one".