664535680 has 32 divisors (see below), whose sum is σ = 1588657140. Its totient is φ = 265814016.

The previous prime is 664535633. The next prime is 664535687. The reversal of 664535680 is 86535466.

It can be written as a sum of positive squares in 2 ways, for example, as 654950464 + 9585216 = 25592^2 + 3096^2 .

It is a tau number, because it is divible by the number of its divisors (32).

It is not an unprimeable number, because it can be changed into a prime (664535687) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 518529 + ... + 519808.

Almost surely, 2^664535680 is an apocalyptic number.

It is an amenable number.

664535680 is an abundant number, since it is smaller than the sum of its proper divisors (924121460).

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

664535680 is a wasteful number, since it uses less digits than its factorization.

664535680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1038356 (or 1038344 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 43.

The square root of 664535680 is about 25778.5895657617. The cubic root of 664535680 is about 872.6486770551.

The spelling of 664535680 in words is "six hundred sixty-four million, five hundred thirty-five thousand, six hundred eighty".