664719818 has 32 divisors (see below), whose sum is σ = 1160282880. Its totient is φ = 279734400.

The previous prime is 664719791. The next prime is 664719829. The reversal of 664719818 is 818917466.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 186380 + ... + 189912.

It is an arithmetic number, because the mean of its divisors is an integer number (36258840).

Almost surely, 2^664719818 is an apocalyptic number.

664719818 is a deficient number, since it is larger than the sum of its proper divisors (495563062).

664719818 is a wasteful number, since it uses less digits than its factorization.

664719818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3782.

The product of its digits is 580608, while the sum is 50.

The square root of 664719818 is about 25782.1608481524. The cubic root of 664719818 is about 872.7292711438.

The spelling of 664719818 in words is "six hundred sixty-four million, seven hundred nineteen thousand, eight hundred eighteen".