721490320 has 20 divisors (see below), whose sum is σ = 1677465180. Its totient is φ = 288596096.

The previous prime is 721490257. The next prime is 721490321. The reversal of 721490320 is 23094127.

It can be written as a sum of positive squares in 2 ways, for example, as 542144656 + 179345664 = 23284^2 + 13392^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is not an unprimeable number, because it can be changed into a prime (721490321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4509235 + ... + 4509394.

It is an arithmetic number, because the mean of its divisors is an integer number (83873259).

Almost surely, 2^721490320 is an apocalyptic number.

It is an amenable number.

721490320 is an abundant number, since it is smaller than the sum of its proper divisors (955974860).

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

721490320 is a wasteful number, since it uses less digits than its factorization.

721490320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9018642 (or 9018636 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 721490320 is about 26860.5718479708. The cubic root of 721490320 is about 896.8989237873.

The spelling of 721490320 in words is "seven hundred twenty-one million, four hundred ninety thousand, three hundred twenty".