721028 has 24 divisors (see below), whose sum is σ = 1573824. Its totient is φ = 280800.

The previous prime is 721013. The next prime is 721037. The reversal of 721028 is 820127.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 863 + ... + 1478.

It is an arithmetic number, because the mean of its divisors is an integer number (65576).

2⁷²¹⁰²⁸ is an apocalyptic number.

It is an amenable number.

721028 is an abundant number, since it is smaller than the sum of its proper divisors (852796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721028 is a wasteful number, since it uses less digits than its factorization.

721028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2363 (or 2361 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 20.

The square root of 721028 is about 849.1336761665. The cubic root of 721028 is about 89.6707309800.

Subtracting 721028 from its reverse (820127), we obtain a palindrome (99099).

The spelling of 721028 in words is "seven hundred twenty-one thousand, twenty-eight".