664040644 has 24 divisors (see below), whose sum is σ = 1181398680. Its totient is φ = 326543616.

The previous prime is 664040623. The next prime is 664040687. The reversal of 664040644 is 446040466.

It can be written as a sum of positive squares in 4 ways, for example, as 63202500 + 600838144 = 7950^2 + 24512^2 .

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54174 + ... + 65290.

It is an arithmetic number, because the mean of its divisors is an integer number (49224945).

Almost surely, 2^664040644 is an apocalyptic number.

It is an amenable number.

664040644 is a deficient number, since it is larger than the sum of its proper divisors (517358036).

664040644 is a wasteful number, since it uses less digits than its factorization.

664040644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11367 (or 11365 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 34.

The square root of 664040644 is about 25768.9860879314. The cubic root of 664040644 is about 872.4319343294.

The spelling of 664040644 in words is "six hundred sixty-four million, forty thousand, six hundred forty-four".