721644500 has 48 divisors (see below), whose sum is σ = 1578879120. Its totient is φ = 288144000.

The previous prime is 721644499. The next prime is 721644541. The reversal of 721644500 is 5446127.

721644500 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 472888516 + 248755984 = 21746^2 + 15772^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 413630 + ... + 415370.

It is an arithmetic number, because the mean of its divisors is an integer number (32893315).

Almost surely, 2^721644500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721644500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (789439560).

721644500 is an abundant number, since it is smaller than the sum of its proper divisors (857234620).

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

721644500 is a wasteful number, since it uses less digits than its factorization.

721644500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2589 (or 2577 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 721644500 is about 26863.4417005714. The cubic root of 721644500 is about 896.9628073087.

The spelling of 721644500 in words is "seven hundred twenty-one million, six hundred forty-four thousand, five hundred".