666006975440 has 80 divisors (see below), whose sum is σ = 1559901499200. Its totient is φ = 264440764416.

The previous prime is 666006975353. The next prime is 666006975449. The reversal of 666006975440 is 44579600666.

It is a happy number.

666006975440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666006975449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8020856 + ... + 8103464.

It is an arithmetic number, because the mean of its divisors is an integer number (19498768740).

Almost surely, 2^666006975440 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 666006975440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779950749600).

666006975440 is an abundant number, since it is smaller than the sum of its proper divisors (893894523760).

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

666006975440 is a wasteful number, since it uses less digits than its factorization.

666006975440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 83364 (or 83358 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 53.

The spelling of 666006975440 in words is "six hundred sixty-six billion, six million, nine hundred seventy-five thousand, four hundred forty".