666344720 has 20 divisors (see below), whose sum is σ = 1549251660. Its totient is φ = 266537856.

The previous prime is 666344719. The next prime is 666344741. The reversal of 666344720 is 27443666.

It can be written as a sum of positive squares in 2 ways, for example, as 518381824 + 147962896 = 22768^2 + 12164^2 .

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

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, 4164575 + ... + 4164734.

It is an arithmetic number, because the mean of its divisors is an integer number (77462583).

Almost surely, 2^666344720 is an apocalyptic number.

It is an amenable number.

666344720 is an abundant number, since it is smaller than the sum of its proper divisors (882906940).

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

666344720 is a wasteful number, since it uses less digits than its factorization.

666344720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8329322 (or 8329316 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 38.

The square root of 666344720 is about 25813.6537514549. The cubic root of 666344720 is about 873.4398189343.

The spelling of 666344720 in words is "six hundred sixty-six million, three hundred forty-four thousand, seven hundred twenty".