666404605440 has 480 divisors, whose sum is σ = 2752349124096. Its totient is φ = 145697587200.

The previous prime is 666404605439. The next prime is 666404605507. The reversal of 666404605440 is 44506404666.

It is a tau number, because it is divible by the number of its divisors (480).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3619615 + ... + 3799265.

Almost surely, 2^666404605440 is an apocalyptic number.

666404605440 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 666404605440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1376174562048).

666404605440 is an abundant number, since it is smaller than the sum of its proper divisors (2085944518656).

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

666404605440 is a wasteful number, since it uses less digits than its factorization.

666404605440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179710 (or 179691 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 45.

The spelling of 666404605440 in words is "six hundred sixty-six billion, four hundred four million, six hundred five thousand, four hundred forty".