640571285 has 16 divisors (see below), whose sum is σ = 797612400. Its totient is φ = 493280256.

The previous prime is 640571279. The next prime is 640571329. The reversal of 640571285 is 582175046.

It can be written as a sum of positive squares in 8 ways, for example, as 35509681 + 605061604 = 5959^2 + 24598^2 .

It is not a de Polignac number, because 640571285 - 2⁶ = 640571221 is a prime.

It is a Curzon number.

It is a congruent 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, 42311 + ... + 55419.

It is an arithmetic number, because the mean of its divisors is an integer number (49850775).

Almost surely, 2^640571285 is an apocalyptic number.

It is an amenable number.

640571285 is a deficient number, since it is larger than the sum of its proper divisors (157041115).

640571285 is a wasteful number, since it uses less digits than its factorization.

640571285 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13480.

The product of its (nonzero) digits is 67200, while the sum is 38.

The square root of 640571285 is about 25309.5097739960. The cubic root of 640571285 is about 862.0302156351.

The spelling of 640571285 in words is "six hundred forty million, five hundred seventy-one thousand, two hundred eighty-five".