664567840 has 48 divisors (see below), whose sum is σ = 1573071192. Its totient is φ = 265314304.

The previous prime is 664567831. The next prime is 664567889. The reversal of 664567840 is 48765466.

It can be written as a sum of positive squares in 4 ways, for example, as 317267344 + 347300496 = 17812^2 + 18636^2 .

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, 85392 + ... + 92848.

Almost surely, 2^664567840 is an apocalyptic number.

It is an amenable number.

664567840 is an abundant number, since it is smaller than the sum of its proper divisors (908503352).

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

664567840 is a wasteful number, since it uses less digits than its factorization.

664567840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8029 (or 8021 counting only the distinct ones).

The product of its (nonzero) digits is 967680, while the sum is 46.

The square root of 664567840 is about 25779.2133316748. The cubic root of 664567840 is about 872.6627540162.

The spelling of 664567840 in words is "six hundred sixty-four million, five hundred sixty-seven thousand, eight hundred forty".