666311817600 has 2304 divisors, whose sum is σ = 3062863964160. Its totient is φ = 135364608000.

The previous prime is 666311817599. The next prime is 666311817641. The reversal of 666311817600 is 6718113666.

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 polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 2170396647 + ... + 2170396953.

It is an arithmetic number, because the mean of its divisors is an integer number (1329368040).

Almost surely, 2^666311817600 is an apocalyptic number.

666311817600 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 666311817600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1531431982080).

666311817600 is an abundant number, since it is smaller than the sum of its proper divisors (2396552146560).

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

666311817600 is a wasteful number, since it uses less digits than its factorization.

666311817600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 409 (or 389 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 45.

The spelling of 666311817600 in words is "six hundred sixty-six billion, three hundred eleven million, eight hundred seventeen thousand, six hundred".