664666511 has 4 divisors (see below), whose sum is σ = 665397024. Its totient is φ = 663936000.

The previous prime is 664666477. The next prime is 664666529. The reversal of 664666511 is 115666466.

664666511 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 115666466 = 2 ⋅57833233.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664666511 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 (664666411) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 363890 + ... + 365711.

It is an arithmetic number, because the mean of its divisors is an integer number (166349256).

Almost surely, 2^664666511 is an apocalyptic number.

664666511 is a deficient number, since it is larger than the sum of its proper divisors (730513).

664666511 is an equidigital number, since it uses as much as digits as its factorization.

664666511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 730512.

The product of its digits is 155520, while the sum is 41.

The square root of 664666511 is about 25781.1270312219. The cubic root of 664666511 is about 872.7059411022.

The spelling of 664666511 in words is "six hundred sixty-four million, six hundred sixty-six thousand, five hundred eleven".