640832539 has 4 divisors (see below), whose sum is σ = 640983456. Its totient is φ = 640681624.

The previous prime is 640832519. The next prime is 640832557. The reversal of 640832539 is 935238046.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 640832539 - 2⁷ = 640832411 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640832519) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 68899 + ... + 77644.

It is an arithmetic number, because the mean of its divisors is an integer number (160245864).

Almost surely, 2^640832539 is an apocalyptic number.

640832539 is a deficient number, since it is larger than the sum of its proper divisors (150917).

640832539 is a wasteful number, since it uses less digits than its factorization.

640832539 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150916.

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 640832539 is about 25314.6704304046. The cubic root of 640832539 is about 862.1473913694.

The spelling of 640832539 in words is "six hundred forty million, eight hundred thirty-two thousand, five hundred thirty-nine".