721844 has 12 divisors (see below), whose sum is σ = 1275204. Its totient is φ = 357504.

The previous prime is 721843. The next prime is 721849. The reversal of 721844 is 448127.

It can be written as a sum of positive squares in 2 ways, for example, as 62500 + 659344 = 250^2 + 812^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721843) 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, 347 + ... + 1250.

It is an arithmetic number, because the mean of its divisors is an integer number (106267).

2⁷²¹⁸⁴⁴ is an apocalyptic number.

It is an amenable number.

721844 is a deficient number, since it is larger than the sum of its proper divisors (553360).

721844 is a wasteful number, since it uses less digits than its factorization.

721844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1714 (or 1712 counting only the distinct ones).

The product of its digits is 1792, while the sum is 26.

The square root of 721844 is about 849.6140300160. The cubic root of 721844 is about 89.7045455387.

The spelling of 721844 in words is "seven hundred twenty-one thousand, eight hundred forty-four".