721328 has 10 divisors (see below), whose sum is σ = 1397604. Its totient is φ = 360656.

The previous prime is 721321. The next prime is 721333. The reversal of 721328 is 823127.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 721328.

It is not an unprimeable number, because it can be changed into a prime (721321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 22526 + ... + 22557.

2⁷²¹³²⁸ is an apocalyptic number.

It is an amenable number.

721328 is a deficient number, since it is larger than the sum of its proper divisors (676276).

721328 is a wasteful number, since it uses less digits than its factorization.

721328 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45091 (or 45085 counting only the distinct ones).

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

The square root of 721328 is about 849.3103084268. The cubic root of 721328 is about 89.6831657672.

The spelling of 721328 in words is "seven hundred twenty-one thousand, three hundred twenty-eight".