666791817795 has 24 divisors (see below), whose sum is σ = 1162157981712. Its totient is φ = 353657534400.

The previous prime is 666791817793. The next prime is 666791817799. The reversal of 666791817795 is 597718197666.

It is not a de Polignac number, because 666791817795 - 2¹ = 666791817793 is a prime.

It is a super-2 number, since 2×666791817795² (a number of 24 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666791817793) 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, 40924441 + ... + 40940730.

It is an arithmetic number, because the mean of its divisors is an integer number (48423249238).

Almost surely, 2^666791817795 is an apocalyptic number.

666791817795 is a deficient number, since it is larger than the sum of its proper divisors (495366163917).

666791817795 is a wasteful number, since it uses less digits than its factorization.

666791817795 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81865363 (or 81865360 counting only the distinct ones).

The product of its digits is 240045120, while the sum is 72.

The spelling of 666791817795 in words is "six hundred sixty-six billion, seven hundred ninety-one million, eight hundred seventeen thousand, seven hundred ninety-five".