664645242 has 16 divisors (see below), whose sum is σ = 1345307040. Its totient is φ = 218878992.

The previous prime is 664645211. The next prime is 664645259. The reversal of 664645242 is 242546466.

It is a self number, because there is not a number n which added to its sum of digits gives 664645242.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 666817 + ... + 667812.

It is an arithmetic number, because the mean of its divisors is an integer number (84081690).

Almost surely, 2^664645242 is an apocalyptic number.

664645242 is an abundant number, since it is smaller than the sum of its proper divisors (680661798).

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

664645242 is a wasteful number, since it uses less digits than its factorization.

664645242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1334717.

The product of its digits is 276480, while the sum is 39.

The square root of 664645242 is about 25780.7145362575. The cubic root of 664645242 is about 872.6966322832.

The spelling of 664645242 in words is "six hundred sixty-four million, six hundred forty-five thousand, two hundred forty-two".