664405556 has 24 divisors (see below), whose sum is σ = 1190962080. Its totient is φ = 324146592.

The previous prime is 664405537. The next prime is 664405579. The reversal of 664405556 is 655504466.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 320090 + ... + 322158.

It is an arithmetic number, because the mean of its divisors is an integer number (49623420).

Almost surely, 2^664405556 is an apocalyptic number.

It is an amenable number.

664405556 is a deficient number, since it is larger than the sum of its proper divisors (526556524).

664405556 is a wasteful number, since it uses less digits than its factorization.

664405556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3983 (or 3981 counting only the distinct ones).

The product of its (nonzero) digits is 432000, while the sum is 41.

The square root of 664405556 is about 25776.0655647832. The cubic root of 664405556 is about 872.5917150026.

The spelling of 664405556 in words is "six hundred sixty-four million, four hundred five thousand, five hundred fifty-six".