640568005 has 16 divisors (see below), whose sum is σ = 958356864. Its totient is φ = 399314880.

The previous prime is 640568003. The next prime is 640568053. The reversal of 640568005 is 500865046.

It is not a de Polignac number, because 640568005 - 2¹ = 640568003 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640568003) 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, 831522 + ... + 832291.

It is an arithmetic number, because the mean of its divisors is an integer number (59897304).

Almost surely, 2^640568005 is an apocalyptic number.

It is an amenable number.

640568005 is a deficient number, since it is larger than the sum of its proper divisors (317788859).

640568005 is a wasteful number, since it uses less digits than its factorization.

640568005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1663836.

The product of its (nonzero) digits is 28800, while the sum is 34.

The square root of 640568005 is about 25309.4449761349. Note that the first 3 decimals coincide. The cubic root of 640568005 is about 862.0287443109.

The spelling of 640568005 in words is "six hundred forty million, five hundred sixty-eight thousand, five".