666785390499 has 24 divisors (see below), whose sum is σ = 1013859709200. Its totient is φ = 421113504960.

The previous prime is 666785390483. The next prime is 666785390507. The reversal of 666785390499 is 994093587666.

It is not a de Polignac number, because 666785390499 - 2⁴ = 666785390483 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666785390429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7847857 + ... + 7932365.

It is an arithmetic number, because the mean of its divisors is an integer number (42244154550).

Almost surely, 2^666785390499 is an apocalyptic number.

666785390499 is a deficient number, since it is larger than the sum of its proper divisors (347074318701).

666785390499 is a wasteful number, since it uses less digits than its factorization.

666785390499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 130675 (or 130672 counting only the distinct ones).

The product of its (nonzero) digits is 529079040, while the sum is 72.

The spelling of 666785390499 in words is "six hundred sixty-six billion, seven hundred eighty-five million, three hundred ninety thousand, four hundred ninety-nine".