666791817761 has 8 divisors (see below), whose sum is σ = 676896621984. Its totient is φ = 656691504480.

The previous prime is 666791817733. The next prime is 666791817793. The reversal of 666791817761 is 167718197666.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666791817761 is a prime.

It is a super-2 number, since 2×666791817761² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (666791817701) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 822935 + ... + 1418028.

It is an arithmetic number, because the mean of its divisors is an integer number (84612077748).

Almost surely, 2^666791817761 is an apocalyptic number.

It is an amenable number.

666791817761 is a deficient number, since it is larger than the sum of its proper divisors (10104804223).

666791817761 is a wasteful number, since it uses less digits than its factorization.

666791817761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2245471.

The product of its digits is 32006016, while the sum is 65.

The spelling of 666791817761 in words is "six hundred sixty-six billion, seven hundred ninety-one million, eight hundred seventeen thousand, seven hundred sixty-one".