720640 has 36 divisors (see below), whose sum is σ = 1729224. Its totient is φ = 287744.

The previous prime is 720619. The next prime is 720653. The reversal of 720640 is 46027.

720640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a zygodrome in base 4.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 999 + ... + 1561.

It is an arithmetic number, because the mean of its divisors is an integer number (48034).

2⁷²⁰⁶⁴⁰ 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 720640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (864612).

720640 is an abundant number, since it is smaller than the sum of its proper divisors (1008584).

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

720640 is an equidigital number, since it uses as much as digits as its factorization.

720640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 584 (or 570 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 720640 is about 848.9051772725. The cubic root of 720640 is about 89.6546435390.

Adding to 720640 its reverse (46027), we get a palindrome (766667).

The spelling of 720640 in words is "seven hundred twenty thousand, six hundred forty".