721808490 has 64 divisors (see below), whose sum is σ = 1869840000. Its totient is φ = 177272064.

The previous prime is 721808489. The next prime is 721808531. The reversal of 721808490 is 94808127.

721808490 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 192756 + ... + 196464.

It is an arithmetic number, because the mean of its divisors is an integer number (29216250).

Almost surely, 2^721808490 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721808490, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (934920000).

721808490 is an abundant number, since it is smaller than the sum of its proper divisors (1148031510).

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

721808490 is a wasteful number, since it uses less digits than its factorization.

721808490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4231.

The product of its (nonzero) digits is 32256, while the sum is 39.

The square root of 721808490 is about 26866.4938166483. The cubic root of 721808490 is about 897.0307455572.

The spelling of 721808490 in words is "seven hundred twenty-one million, eight hundred eight thousand, four hundred ninety".