666556515072 has 576 divisors, whose sum is σ = 2313614392320. Its totient is φ = 185330073600.

The previous prime is 666556515049. The next prime is 666556515133. The reversal of 666556515072 is 270515655666.

It is a tau number, because it is divible by the number of its divisors (576).

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

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 63 ways as a sum of consecutive naturals, for example, 875895172 + ... + 875895932.

Almost surely, 2^666556515072 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 666556515072, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1156807196160).

666556515072 is an abundant number, since it is smaller than the sum of its proper divisors (1647057877248).

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

666556515072 is a wasteful number, since it uses less digits than its factorization.

666556515072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1257 (or 1237 counting only the distinct ones).

The product of its (nonzero) digits is 11340000, while the sum is 54.

The spelling of 666556515072 in words is "six hundred sixty-six billion, five hundred fifty-six million, five hundred fifteen thousand, seventy-two".