646111665 has 24 divisors (see below), whose sum is σ = 1131480168. Its totient is φ = 341038080.

The previous prime is 646111643. The next prime is 646111667. The reversal of 646111665 is 566111646.

It is a happy number.

646111665 is a `hidden beast` number, since 646 + 1 + 1 + 1 + 6 + 6 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 129140496 + 516971169 = 11364^2 + 22737^2 .

It is not a de Polignac number, because 646111665 - 2⁵ = 646111633 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646111667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69646 + ... + 78375.

It is an arithmetic number, because the mean of its divisors is an integer number (47145007).

Almost surely, 2^646111665 is an apocalyptic number.

It is an amenable number.

646111665 is a deficient number, since it is larger than the sum of its proper divisors (485368503).

646111665 is a wasteful number, since it uses less digits than its factorization.

646111665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 148129 (or 148126 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 646111665 is about 25418.7266596893. The cubic root of 646111665 is about 864.5083532647.

The spelling of 646111665 in words is "six hundred forty-six million, one hundred eleven thousand, six hundred sixty-five".