666756117 has 10 divisors (see below), whose sum is σ = 996018518. Its totient is φ = 444504024.

The previous prime is 666756073. The next prime is 666756127. The reversal of 666756117 is 711657666.

It can be written as a sum of positive squares in only one way, i.e., 406062801 + 260693316 = 20151^2 + 16146^2 .

It is not a de Polignac number, because 666756117 - 2¹⁸ = 666493973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666756127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 4115698 + ... + 4115859.

Almost surely, 2^666756117 is an apocalyptic number.

It is an amenable number.

666756117 is a deficient number, since it is larger than the sum of its proper divisors (329262401).

666756117 is an equidigital number, since it uses as much as digits as its factorization.

666756117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8231569 (or 8231560 counting only the distinct ones).

The product of its digits is 317520, while the sum is 45.

The square root of 666756117 is about 25821.6211148719. The cubic root of 666756117 is about 873.6195340209.

The spelling of 666756117 in words is "six hundred sixty-six million, seven hundred fifty-six thousand, one hundred seventeen".