328445721 has 12 divisors (see below), whose sum is σ = 474692400. Its totient is φ = 218838840.

The previous prime is 328445693. The next prime is 328445731. The reversal of 328445721 is 127544823.

It is a happy number.

328445721 is a `hidden beast` number, since 3 + 2 + 84 + 4 + 572 + 1 = 666.

It is not a de Polignac number, because 328445721 - 2⁶ = 328445657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (328445731) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7930 + ... + 26828.

It is an arithmetic number, because the mean of its divisors is an integer number (39557700).

Almost surely, 2^328445721 is an apocalyptic number.

It is an amenable number.

328445721 is a deficient number, since it is larger than the sum of its proper divisors (146246679).

328445721 is a wasteful number, since it uses less digits than its factorization.

328445721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20836 (or 20833 counting only the distinct ones).

The product of its digits is 53760, while the sum is 36.

The square root of 328445721 is about 18123.0715111981. The cubic root of 328445721 is about 689.9556934373.

The spelling of 328445721 in words is "three hundred twenty-eight million, four hundred forty-five thousand, seven hundred twenty-one".