666717717666 has 96 divisors (see below), whose sum is σ = 1822317473088. Its totient is φ = 159852389760.

The previous prime is 666717717661. The next prime is 666717717769.

666717717666 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 666717717597 and 666717717606.

It is not an unprimeable number, because it can be changed into a prime (666717717661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 7887145 + ... + 7971228.

It is an arithmetic number, because the mean of its divisors is an integer number (18982473678).

Almost surely, 2^666717717666 is an apocalyptic number.

666717717666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

666717717666 is an abundant number, since it is smaller than the sum of its proper divisors (1155599755422).

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

666717717666 is a wasteful number, since it uses less digits than its factorization.

666717717666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15858416 (or 15858409 counting only the distinct ones).

The product of its digits is 112021056, while the sum is 66.

The spelling of 666717717666 in words is "six hundred sixty-six billion, seven hundred seventeen million, seven hundred seventeen thousand, six hundred sixty-six".