723665664 has 108 divisors (see below), whose sum is σ = 2163970536. Its totient is φ = 241201152.

The previous prime is 723665651. The next prime is 723665671. The reversal of 723665664 is 466566327.

723665664 is a `hidden beast` number, since 7 + 23 + 66 + 566 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (108).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 56392 + ... + 68024.

Almost surely, 2^723665664 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 723665664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1081985268).

723665664 is an abundant number, since it is smaller than the sum of its proper divisors (1440304872).

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

723665664 is an equidigital number, since it uses as much as digits as its factorization.

723665664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11664 (or 11638 counting only the distinct ones).

The product of its digits is 1088640, while the sum is 45.

The square root of 723665664 is about 26901.0346269433. The cubic root of 723665664 is about 897.7994237902.

It can be divided in two parts, 7236 and 65664, that added together give a square (72900 = 270²).

The spelling of 723665664 in words is "seven hundred twenty-three million, six hundred sixty-five thousand, six hundred sixty-four".