721804 has 12 divisors (see below), whose sum is σ = 1304128. Its totient is φ = 349200.

The previous prime is 721793. The next prime is 721843. The reversal of 721804 is 408127.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2787 + ... + 3034.

2⁷²¹⁸⁰⁴ is an apocalyptic number.

It is an amenable number.

721804 is a deficient number, since it is larger than the sum of its proper divisors (582324).

721804 is a wasteful number, since it uses less digits than its factorization.

721804 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5856 (or 5854 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 721804 is about 849.5904895890. The cubic root of 721804 is about 89.7028885564.

It can be divided in two parts, 7 and 21804, that multiplied together give a triangular number (152628 = T₅₅₂).

The spelling of 721804 in words is "seven hundred twenty-one thousand, eight hundred four".