640571305 has 16 divisors (see below), whose sum is σ = 887894784. Its totient is φ = 438465280.

The previous prime is 640571279. The next prime is 640571329. The reversal of 640571305 is 503175046.

It is not a de Polignac number, because 640571305 - 2⁵ = 640571273 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 341617 + ... + 343486.

It is an arithmetic number, because the mean of its divisors is an integer number (55493424).

Almost surely, 2^640571305 is an apocalyptic number.

It is an amenable number.

640571305 is a deficient number, since it is larger than the sum of its proper divisors (247323479).

640571305 is a wasteful number, since it uses less digits than its factorization.

640571305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685136.

The product of its (nonzero) digits is 12600, while the sum is 31.

The square root of 640571305 is about 25309.5101691044. The cubic root of 640571305 is about 862.0302246065.

The spelling of 640571305 in words is "six hundred forty million, five hundred seventy-one thousand, three hundred five".