640021696 has 14 divisors (see below), whose sum is σ = 1270043180. Its totient is φ = 320010816.

The previous prime is 640021687. The next prime is 640021703. The reversal of 640021696 is 696120046.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5000106 + ... + 5000233.

It is an arithmetic number, because the mean of its divisors is an integer number (90717370).

Almost surely, 2^640021696 is an apocalyptic number.

It is an amenable number.

640021696 is a deficient number, since it is larger than the sum of its proper divisors (630021484).

640021696 is a wasteful number, since it uses less digits than its factorization.

640021696 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10000351 (or 10000341 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 34.

The square root of 640021696 is about 25298.6500825637. The cubic root of 640021696 is about 861.7836139475.

The spelling of 640021696 in words is "six hundred forty million, twenty-one thousand, six hundred ninety-six".