640021468 has 12 divisors (see below), whose sum is σ = 1120333032. Its totient is φ = 319926320.

The previous prime is 640021433. The next prime is 640021471. The reversal of 640021468 is 864120046.

It is a congruent number.

It is an unprimeable number.

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, 2155 + ... + 35842.

It is an arithmetic number, because the mean of its divisors is an integer number (93361086).

Almost surely, 2^640021468 is an apocalyptic number.

It is an amenable number.

640021468 is a deficient number, since it is larger than the sum of its proper divisors (480311564).

640021468 is a wasteful number, since it uses less digits than its factorization.

640021468 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 42212 (or 42210 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 31.

The square root of 640021468 is about 25298.6455763940. The cubic root of 640021468 is about 861.7835116142.

The spelling of 640021468 in words is "six hundred forty million, twenty-one thousand, four hundred sixty-eight".