31233220321 has 4 divisors (see below), whose sum is σ = 31236631444. Its totient is φ = 31229809200.

The previous prime is 31233220259. The next prime is 31233220327. The reversal of 31233220321 is 12302233213.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12302233213 = 193 ⋅63742141.

It can be written as a sum of positive squares in 2 ways, for example, as 9454839696 + 21778380625 = 97236^2 + 147575^2 .

It is a cyclic number.

It is not a de Polignac number, because 31233220321 - 2¹⁵ = 31233187553 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31233220292 and 31233220301.

It is not an unprimeable number, because it can be changed into a prime (31233220327) 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, 1691790 + ... + 1710151.

It is an arithmetic number, because the mean of its divisors is an integer number (7809157861).

Almost surely, 2^31233220321 is an apocalyptic number.

It is an amenable number.

31233220321 is a deficient number, since it is larger than the sum of its proper divisors (3411123).

31233220321 is an equidigital number, since it uses as much as digits as its factorization.

31233220321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3411122.

The product of its (nonzero) digits is 1296, while the sum is 22.

Adding to 31233220321 its reverse (12302233213), we get a palindrome (43535453534).

The spelling of 31233220321 in words is "thirty-one billion, two hundred thirty-three million, two hundred twenty thousand, three hundred twenty-one".