640324388 has 48 divisors (see below), whose sum is σ = 1268386560. Its totient is φ = 280300800.

The previous prime is 640324369. The next prime is 640324417. The reversal of 640324388 is 883423046.

It is a super-5 number, since 5×640324388⁵ (a number of 45 digits) contains 55555 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140270 + ... + 144762.

It is an arithmetic number, because the mean of its divisors is an integer number (26424720).

Almost surely, 2^640324388 is an apocalyptic number.

It is an amenable number.

640324388 is a deficient number, since it is larger than the sum of its proper divisors (628062172).

640324388 is a wasteful number, since it uses less digits than its factorization.

640324388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4628 (or 4626 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 38.

The square root of 640324388 is about 25304.6317499386. The cubic root of 640324388 is about 861.9194499122.

The spelling of 640324388 in words is "six hundred forty million, three hundred twenty-four thousand, three hundred eighty-eight".