666394408800 has 288 divisors, whose sum is σ = 2411365975200. Its totient is φ = 177613793280.

The previous prime is 666394408793. The next prime is 666394408831. The reversal of 666394408800 is 8804493666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a hoax number, since the sum of its digits (54) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 49003602 + ... + 49017198.

It is an arithmetic number, because the mean of its divisors is an integer number (8372798525).

Almost surely, 2^666394408800 is an apocalyptic number.

666394408800 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666394408800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1205682987600).

666394408800 is an abundant number, since it is smaller than the sum of its proper divisors (1744971566400).

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

666394408800 is a wasteful number, since it uses less digits than its factorization.

666394408800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15895 (or 15876 counting only the distinct ones).

The product of its (nonzero) digits is 5971968, while the sum is 54.

The spelling of 666394408800 in words is "six hundred sixty-six billion, three hundred ninety-four million, four hundred eight thousand, eight hundred".