666791817798 has 32 divisors (see below), whose sum is σ = 1344525557760. Its totient is φ = 220441435200.

The previous prime is 666791817793. The next prime is 666791817799. The reversal of 666791817798 is 897718197666.

It is a super-2 number, since 2×666791817798² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

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 15 ways as a sum of consecutive naturals, for example, 2204098 + ... + 2488298.

It is an arithmetic number, because the mean of its divisors is an integer number (42016423680).

Almost surely, 2^666791817798 is an apocalyptic number.

666791817798 is an abundant number, since it is smaller than the sum of its proper divisors (677733739962).

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

666791817798 is a wasteful number, since it uses less digits than its factorization.

666791817798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287412.

The product of its digits is 384072192, while the sum is 75.

The spelling of 666791817798 in words is "six hundred sixty-six billion, seven hundred ninety-one million, eight hundred seventeen thousand, seven hundred ninety-eight".