640933688 has 16 divisors (see below), whose sum is σ = 1265001000. Its totient is φ = 303600096.

The previous prime is 640933681. The next prime is 640933693. The reversal of 640933688 is 886339046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640933681) 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, 2108183 + ... + 2108486.

Almost surely, 2^640933688 is an apocalyptic number.

It is an amenable number.

640933688 is a deficient number, since it is larger than the sum of its proper divisors (624067312).

640933688 is a wasteful number, since it uses less digits than its factorization.

640933688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4216694 (or 4216690 counting only the distinct ones).

The product of its (nonzero) digits is 746496, while the sum is 47.

The square root of 640933688 is about 25316.6681852095. The cubic root of 640933688 is about 862.1927494275.

The spelling of 640933688 in words is "six hundred forty million, nine hundred thirty-three thousand, six hundred eighty-eight".