666810880 has 80 divisors (see below), whose sum is σ = 1638035784. Its totient is φ = 260177920.

The previous prime is 666810863. The next prime is 666810887. The reversal of 666810880 is 88018666.

It is a happy number.

666810880 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 346257664 + 320553216 = 18608^2 + 17904^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (666810887) 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, 101784 + ... + 108136.

Almost surely, 2^666810880 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 666810880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (819017892).

666810880 is an abundant number, since it is smaller than the sum of its proper divisors (971224904).

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

666810880 is an equidigital number, since it uses as much as digits as its factorization.

666810880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6417 (or 6401 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 43.

The square root of 666810880 is about 25822.6815028959. The cubic root of 666810880 is about 873.6434511702.

The spelling of 666810880 in words is "six hundred sixty-six million, eight hundred ten thousand, eight hundred eighty".