664640424 has 64 divisors (see below), whose sum is σ = 2109974400. Its totient is φ = 189896832.

The previous prime is 664640419. The next prime is 664640437. The reversal of 664640424 is 424046466.

It is a happy number.

664640424 is a `hidden beast` number, since 6 + 6 + 4 + 640 + 4 + 2 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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, 218277 + ... + 221300.

It is an arithmetic number, because the mean of its divisors is an integer number (32968350).

Almost surely, 2^664640424 is an apocalyptic number.

It is an amenable number.

664640424 is an abundant number, since it is smaller than the sum of its proper divisors (1445333976).

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

664640424 is a wasteful number, since it uses less digits than its factorization.

664640424 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439599 (or 439589 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 36.

The square root of 664640424 is about 25780.6210941474. The cubic root of 664640424 is about 872.6945235580.

The spelling of 664640424 in words is "six hundred sixty-four million, six hundred forty thousand, four hundred twenty-four".