666378880 has 128 divisors (see below), whose sum is σ = 1657687680. Its totient is φ = 255946752.

The previous prime is 666378877. The next prime is 666378893. The reversal of 666378880 is 88873666.

It is a tau number, because it is divible by the number of its divisors (128).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2533629 + ... + 2533891.

It is an arithmetic number, because the mean of its divisors is an integer number (12950685).

Almost surely, 2^666378880 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 666378880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (828843840).

666378880 is an abundant number, since it is smaller than the sum of its proper divisors (991308800).

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

666378880 is a wasteful number, since it uses less digits than its factorization.

666378880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 426 (or 414 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 52.

The square root of 666378880 is about 25814.3154083156. The cubic root of 666378880 is about 873.4547442392.

The spelling of 666378880 in words is "six hundred sixty-six million, three hundred seventy-eight thousand, eight hundred eighty".