721288 has 16 divisors (see below), whose sum is σ = 1399500. Its totient is φ = 348096.

The previous prime is 721283. The next prime is 721291. The reversal of 721288 is 882127.

It can be written as a sum of positive squares in 2 ways, for example, as 702244 + 19044 = 838^2 + 138^2 .

It is not an unprimeable number, because it can be changed into a prime (721283) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1323 + ... + 1786.

2⁷²¹²⁸⁸ is an apocalyptic number.

It is an amenable number.

721288 is a deficient number, since it is larger than the sum of its proper divisors (678212).

721288 is a wasteful number, since it uses less digits than its factorization.

721288 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3144 (or 3140 counting only the distinct ones).

The product of its digits is 1792, while the sum is 28.

The square root of 721288 is about 849.2867595812. The cubic root of 721288 is about 89.6815079948.

The spelling of 721288 in words is "seven hundred twenty-one thousand, two hundred eighty-eight".