31304321 has 2 divisors, whose sum is σ = 31304322. Its totient is φ = 31304320.

The previous prime is 31304309. The next prime is 31304323. The reversal of 31304321 is 12340313.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28206721 + 3097600 = 5311^2 + 1760^2 .

It is an emirp because it is prime and its reverse (12340313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31304321 - 2¹⁸ = 31042177 is a prime.

Together with 31304323, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31304321.

It is not a weakly prime, because it can be changed into another prime (31304323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15652160 + 15652161.

It is an arithmetic number, because the mean of its divisors is an integer number (15652161).

Almost surely, 2^31304321 is an apocalyptic number.

It is an amenable number.

31304321 is a deficient number, since it is larger than the sum of its proper divisors (1).

31304321 is an equidigital number, since it uses as much as digits as its factorization.

31304321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 31304321 is about 5595.0264521269. The cubic root of 31304321 is about 315.1626639503.

Adding to 31304321 its reverse (12340313), we get a palindrome (43644634).

The spelling of 31304321 in words is "thirty-one million, three hundred four thousand, three hundred twenty-one".