720664 has 32 divisors (see below), whose sum is σ = 1637280. Its totient is φ = 290304.

The previous prime is 720661. The next prime is 720677. The reversal of 720664 is 466027.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (720661) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 574 + ... + 1330.

It is an arithmetic number, because the mean of its divisors is an integer number (51165).

2⁷²⁰⁶⁶⁴ 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 720664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818640).

720664 is an abundant number, since it is smaller than the sum of its proper divisors (916616).

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

720664 is a wasteful number, since it uses less digits than its factorization.

720664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 787 (or 783 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 720664 is about 848.9193130092. The cubic root of 720664 is about 89.6556388060.

The spelling of 720664 in words is "seven hundred twenty thousand, six hundred sixty-four".