328721 has 2 divisors, whose sum is σ = 328722. Its totient is φ = 328720.

The previous prime is 328709. The next prime is 328753. The reversal of 328721 is 127823.

328721 is nontrivially palindromic in base 8.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 261121 + 67600 = 511^2 + 260^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-328721 is a prime.

It is a Chen prime.

It is a d-powerful number, because it can be written as 3² + 2¹⁰ + 7 + 8⁶ + 2¹⁶ + 1 .

It is not a weakly prime, because it can be changed into another prime (328781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 164360 + 164361.

It is an arithmetic number, because the mean of its divisors is an integer number (164361).

2³²⁸⁷²¹ is an apocalyptic number.

It is an amenable number.

328721 is a deficient number, since it is larger than the sum of its proper divisors (1).

328721 is an equidigital number, since it uses as much as digits as its factorization.

328721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 672, while the sum is 23.

The square root of 328721 is about 573.3419572995. The cubic root of 328721 is about 69.0148396284.

The spelling of 328721 in words is "three hundred twenty-eight thousand, seven hundred twenty-one".