31031123111021 has 12 divisors (see below), whose sum is σ = 34144991900796. Its totient is φ = 28180004973120.

The previous prime is 31031123110987. The next prime is 31031123111029. The reversal of 31031123111021 is 12011132113013.

It can be written as a sum of positive squares in 2 ways, for example, as 5637485686921 + 25393637424100 = 2374339^2 + 5039210^2 .

It is not a de Polignac number, because 31031123111021 - 2⁶ = 31031123110957 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31031123110984 and 31031123111002.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31031123111029) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136735910 + ... + 136962663.

It is an arithmetic number, because the mean of its divisors is an integer number (2845415991733).

Almost surely, 2^{31031123111021} is an apocalyptic number.

It is an amenable number.

31031123111021 is a deficient number, since it is larger than the sum of its proper divisors (3113868789775).

31031123111021 is a wasteful number, since it uses less digits than its factorization.

31031123111021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273699532 (or 273699521 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 20.

Adding to 31031123111021 its reverse (12011132113013), we get a palindrome (43042255224034).

The spelling of 31031123111021 in words is "thirty-one trillion, thirty-one billion, one hundred twenty-three million, one hundred eleven thousand, twenty-one".