31213023331 has 4 divisors (see below), whose sum is σ = 35672026672. Its totient is φ = 26754019992.

The previous prime is 31213023329. The next prime is 31213023343. The reversal of 31213023331 is 13332031213.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 31213023331 - 2¹ = 31213023329 is a prime.

It is a super-2 number, since 2×31213023331² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31213023631) 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, 2229501660 + ... + 2229501673.

It is an arithmetic number, because the mean of its divisors is an integer number (8918006668).

Almost surely, 2^31213023331 is an apocalyptic number.

31213023331 is a deficient number, since it is larger than the sum of its proper divisors (4459003341).

31213023331 is an equidigital number, since it uses as much as digits as its factorization.

31213023331 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4459003340.

The product of its (nonzero) digits is 972, while the sum is 22.

Adding to 31213023331 its reverse (13332031213), we get a palindrome (44545054544).

The spelling of 31213023331 in words is "thirty-one billion, two hundred thirteen million, twenty-three thousand, three hundred thirty-one".