328071721 has 2 divisors, whose sum is σ = 328071722. Its totient is φ = 328071720.

The previous prime is 328071719. The next prime is 328071739. The reversal of 328071721 is 127170823.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204061225 + 124010496 = 14285^2 + 11136^2 .

It is a cyclic number.

It is not a de Polignac number, because 328071721 - 2¹ = 328071719 is a prime.

Together with 328071719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (328071761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 164035860 + 164035861.

It is an arithmetic number, because the mean of its divisors is an integer number (164035861).

Almost surely, 2^328071721 is an apocalyptic number.

It is an amenable number.

328071721 is a deficient number, since it is larger than the sum of its proper divisors (1).

328071721 is an equidigital number, since it uses as much as digits as its factorization.

328071721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4704, while the sum is 31.

The square root of 328071721 is about 18112.7502329160. The cubic root of 328071721 is about 689.6937105898.

The spelling of 328071721 in words is "three hundred twenty-eight million, seventy-one thousand, seven hundred twenty-one".