721504 has 24 divisors (see below), whose sum is σ = 1623888. Its totient is φ = 309120.

The previous prime is 721499. The next prime is 721529. The reversal of 721504 is 405127.

It is a congruent number.

It is an unprimeable number.

721504 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1387 + ... + 1834.

It is an arithmetic number, because the mean of its divisors is an integer number (67662).

2⁷²¹⁵⁰⁴ is an apocalyptic number.

It is an amenable number.

721504 is an abundant number, since it is smaller than the sum of its proper divisors (902384).

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

721504 is a wasteful number, since it uses less digits than its factorization.

721504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3238 (or 3230 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 721504 is about 849.4139155912. The cubic root of 721504 is about 89.6904592378.

It can be divided in two parts, 721 and 504, that added together give a triangular number (1225 = T₄₉).

The spelling of 721504 in words is "seven hundred twenty-one thousand, five hundred four".