664731636 has 24 divisors (see below), whose sum is σ = 1601074944. Its totient is φ = 214429440.

The previous prime is 664731631. The next prime is 664731659. The reversal of 664731636 is 636137466.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664731631) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 893085 + ... + 893828.

It is an arithmetic number, because the mean of its divisors is an integer number (66711456).

Almost surely, 2^664731636 is an apocalyptic number.

It is an amenable number.

664731636 is an abundant number, since it is smaller than the sum of its proper divisors (936343308).

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

664731636 is a wasteful number, since it uses less digits than its factorization.

664731636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1786951 (or 1786949 counting only the distinct ones).

The product of its digits is 326592, while the sum is 42.

The square root of 664731636 is about 25782.3900366122. The cubic root of 664731636 is about 872.7344431742.

It can be divided in two parts, 6647 and 31636, that added together give a palindrome (38283).

The spelling of 664731636 in words is "six hundred sixty-four million, seven hundred thirty-one thousand, six hundred thirty-six".