666989558784 has 704 divisors, whose sum is σ = 2119264012800. Its totient is φ = 206900822016.

The previous prime is 666989558731. The next prime is 666989558791. The reversal of 666989558784 is 487855989666.

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 63 ways as a sum of consecutive naturals, for example, 2595289984 + ... + 2595290240.

It is an arithmetic number, because the mean of its divisors is an integer number (3010318200).

Almost surely, 2^666989558784 is an apocalyptic number.

666989558784 is a gapful number since it is divisible by the number (64) 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 666989558784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059632006400).

666989558784 is an abundant number, since it is smaller than the sum of its proper divisors (1452274454016).

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

666989558784 is a wasteful number, since it uses less digits than its factorization.

666989558784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425 (or 401 counting only the distinct ones).

The product of its digits is 6270566400, while the sum is 81.

The spelling of 666989558784 in words is "six hundred sixty-six billion, nine hundred eighty-nine million, five hundred fifty-eight thousand, seven hundred eighty-four".