31032013021 has 4 divisors (see below), whose sum is σ = 31032519100. Its totient is φ = 31031506944.

The previous prime is 31032013009. The next prime is 31032013069. The reversal of 31032013021 is 12031023013.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12031023013 = 4919 ⋅2445827.

It can be written as a sum of positive squares in 2 ways, for example, as 25531565796 + 5500447225 = 159786^2 + 74165^2 .

It is a cyclic number.

It is not a de Polignac number, because 31032013021 - 2²¹ = 31029915869 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31032012986 and 31032013004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31032013081) 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, 145956 + ... + 288733.

It is an arithmetic number, because the mean of its divisors is an integer number (7758129775).

Almost surely, 2^31032013021 is an apocalyptic number.

It is an amenable number.

31032013021 is a deficient number, since it is larger than the sum of its proper divisors (506079).

31032013021 is an equidigital number, since it uses as much as digits as its factorization.

31032013021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 506078.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 31032013021 its reverse (12031023013), we get a palindrome (43063036034).

The spelling of 31032013021 in words is "thirty-one billion, thirty-two million, thirteen thousand, twenty-one".