721728450 has 72 divisors (see below), whose sum is σ = 1949976756. Its totient is φ = 191376000.

The previous prime is 721728439. The next prime is 721728457. The reversal of 721728450 is 54827127.

It can be written as a sum of positive squares in 6 ways, for example, as 259435449 + 462293001 = 16107^2 + 21501^2 .

It is not an unprimeable number, because it can be changed into a prime (721728457) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 77020 + ... + 85880.

Almost surely, 2^721728450 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721728450, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (974988378).

721728450 is an abundant number, since it is smaller than the sum of its proper divisors (1228248306).

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

721728450 is a wasteful number, since it uses less digits than its factorization.

721728450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9060 (or 9052 counting only the distinct ones).

The product of its (nonzero) digits is 31360, while the sum is 36.

The square root of 721728450 is about 26865.0041876044. The cubic root of 721728450 is about 896.9975876417.

The spelling of 721728450 in words is "seven hundred twenty-one million, seven hundred twenty-eight thousand, four hundred fifty".