640308895 has 16 divisors (see below), whose sum is σ = 782369280. Its totient is φ = 502990624.

The previous prime is 640308863. The next prime is 640308899. The reversal of 640308895 is 598803046.

It is not a de Polignac number, because 640308895 - 2⁵ = 640308863 is a prime.

It is a super-2 number, since 2×640308895² = 819990962032242050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640308899) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64686 + ... + 73924.

It is an arithmetic number, because the mean of its divisors is an integer number (48898080).

Almost surely, 2^640308895 is an apocalyptic number.

640308895 is a deficient number, since it is larger than the sum of its proper divisors (142060385).

640308895 is a wasteful number, since it uses less digits than its factorization.

640308895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9494.

The product of its (nonzero) digits is 207360, while the sum is 43.

The square root of 640308895 is about 25304.3256183602. The cubic root of 640308895 is about 861.9124983181.

The spelling of 640308895 in words is "six hundred forty million, three hundred eight thousand, eight hundred ninety-five".