31131331321121 has 4 divisors (see below), whose sum is σ = 31131480105492. Its totient is φ = 31131182536752.

The previous prime is 31131331321009. The next prime is 31131331321141. The reversal of 31131331321121 is 12112313313113.

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 23898028650721 + 7233302670400 = 4888561^2 + 2689480^2 .

It is a cyclic number.

It is not a de Polignac number, because 31131331321121 - 2¹⁴ = 31131331304737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31131331321141) 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, 74077886 + ... + 74496951.

It is an arithmetic number, because the mean of its divisors is an integer number (7782870026373).

Almost surely, 2^{31131331321121} is an apocalyptic number.

It is an amenable number.

31131331321121 is a deficient number, since it is larger than the sum of its proper divisors (148784371).

31131331321121 is a wasteful number, since it uses less digits than its factorization.

31131331321121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148784370.

The product of its digits is 972, while the sum is 26.

Adding to 31131331321121 its reverse (12112313313113), we get a palindrome (43243644634234).

The spelling of 31131331321121 in words is "thirty-one trillion, one hundred thirty-one billion, three hundred thirty-one million, three hundred twenty-one thousand, one hundred twenty-one".