664675812 has 18 divisors (see below), whose sum is σ = 1680152838. Its totient is φ = 221558592.

The previous prime is 664675799. The next prime is 664675813. The reversal of 664675812 is 218576466.

664675812 is a `hidden beast` number, since 6 + 6 + 4 + 67 + 581 + 2 = 666.

It can be written as a sum of positive squares in only one way, i.e., 506520036 + 158155776 = 22506^2 + 12576^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is not an unprimeable number, because it can be changed into a prime (664675813) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 9231573 + ... + 9231644.

Almost surely, 2^664675812 is an apocalyptic number.

It is an amenable number.

664675812 is an abundant number, since it is smaller than the sum of its proper divisors (1015477026).

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

664675812 is a wasteful number, since it uses less digits than its factorization.

664675812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18463227 (or 18463222 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The square root of 664675812 is about 25781.3074144815. The cubic root of 664675812 is about 872.7100118153.

The spelling of 664675812 in words is "six hundred sixty-four million, six hundred seventy-five thousand, eight hundred twelve".