640665336 has 16 divisors (see below), whose sum is σ = 1601663400. Its totient is φ = 213555104.

The previous prime is 640665331. The next prime is 640665373. The reversal of 640665336 is 633566046.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 640665294 and 640665303.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640665331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13347171 + ... + 13347218.

Almost surely, 2^640665336 is an apocalyptic number.

It is an amenable number.

640665336 is an abundant number, since it is smaller than the sum of its proper divisors (960998064).

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

640665336 is a wasteful number, since it uses less digits than its factorization.

640665336 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26694398 (or 26694394 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 39.

The square root of 640665336 is about 25311.3677228237. The cubic root of 640665336 is about 862.0724023717.

The spelling of 640665336 in words is "six hundred forty million, six hundred sixty-five thousand, three hundred thirty-six".