320349721 has 2 divisors, whose sum is σ = 320349722. Its totient is φ = 320349720.

The previous prime is 320349719. The next prime is 320349749. The reversal of 320349721 is 127943023.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 314565696 + 5784025 = 17736^2 + 2405^2 .

It is a cyclic number.

It is not a de Polignac number, because 320349721 - 2¹ = 320349719 is a prime.

Together with 320349719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (320389721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160174860 + 160174861.

It is an arithmetic number, because the mean of its divisors is an integer number (160174861).

Almost surely, 2^320349721 is an apocalyptic number.

It is an amenable number.

320349721 is a deficient number, since it is larger than the sum of its proper divisors (1).

320349721 is an equidigital number, since it uses as much as digits as its factorization.

320349721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 320349721 is about 17898.3161498505. The cubic root of 320349721 is about 684.2394606615.

The spelling of 320349721 in words is "three hundred twenty million, three hundred forty-nine thousand, seven hundred twenty-one".