664544605 has 16 divisors (see below), whose sum is σ = 838991664. Its totient is φ = 504645120.

The previous prime is 664544597. The next prime is 664544651. The reversal of 664544605 is 506445466.

It can be written as a sum of positive squares in 8 ways, for example, as 10310521 + 654234084 = 3211^2 + 25578^2 .

It is not a de Polignac number, because 664544605 - 2³ = 664544597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36222 + ... + 51391.

It is an arithmetic number, because the mean of its divisors is an integer number (52436979).

Almost surely, 2^664544605 is an apocalyptic number.

It is an amenable number.

664544605 is a deficient number, since it is larger than the sum of its proper divisors (174447059).

664544605 is a wasteful number, since it uses less digits than its factorization.

664544605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87696.

The product of its (nonzero) digits is 345600, while the sum is 40.

The square root of 664544605 is about 25778.7626739531. The cubic root of 664544605 is about 872.6525837199.

The spelling of 664544605 in words is "six hundred sixty-four million, five hundred forty-four thousand, six hundred five".