640239816 has 16 divisors (see below), whose sum is σ = 1600599600. Its totient is φ = 213413264.

The previous prime is 640239797. The next prime is 640239829. The reversal of 640239816 is 618932046.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13338306 + ... + 13338353.

It is an arithmetic number, because the mean of its divisors is an integer number (100037475).

Almost surely, 2^640239816 is an apocalyptic number.

It is an amenable number.

640239816 is an abundant number, since it is smaller than the sum of its proper divisors (960359784).

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

640239816 is a wasteful number, since it uses less digits than its factorization.

640239816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26676668 (or 26676664 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 39.

The square root of 640239816 is about 25302.9606172875. The cubic root of 640239816 is about 861.8815017188.

The spelling of 640239816 in words is "six hundred forty million, two hundred thirty-nine thousand, eight hundred sixteen".