640752386 has 8 divisors (see below), whose sum is σ = 961596684. Its totient is φ = 320220160.

The previous prime is 640752379. The next prime is 640752397. The reversal of 640752386 is 683257046.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 588984361 + 51768025 = 24269^2 + 7195^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

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, 72815 + ... + 81138.

Almost surely, 2^640752386 is an apocalyptic number.

640752386 is a deficient number, since it is larger than the sum of its proper divisors (320844298).

640752386 is a wasteful number, since it uses less digits than its factorization.

640752386 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156036.

The product of its (nonzero) digits is 241920, while the sum is 41.

The square root of 640752386 is about 25313.0872475089. The cubic root of 640752386 is about 862.1114451188. Note that the first 3 decimals are identical.

The spelling of 640752386 in words is "six hundred forty million, seven hundred fifty-two thousand, three hundred eighty-six".