640163205 has 72 divisors (see below), whose sum is σ = 1234298520. Its totient is φ = 306662400.

The previous prime is 640163191. The next prime is 640163243. The reversal of 640163205 is 502361046.

640163205 is a `hidden beast` number, since 640 + 16 + 3 + 2 + 0 + 5 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 101969604 + 538193601 = 10098^2 + 23199^2 .

It is not a de Polignac number, because 640163205 - 2¹¹ = 640161157 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 483945 + ... + 485265.

It is an arithmetic number, because the mean of its divisors is an integer number (17143035).

Almost surely, 2^640163205 is an apocalyptic number.

It is an amenable number.

640163205 is a deficient number, since it is larger than the sum of its proper divisors (594135315).

640163205 is a wasteful number, since it uses less digits than its factorization.

640163205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1443 (or 1429 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 640163205 is about 25301.4466977681. The cubic root of 640163205 is about 861.8471228106.

The spelling of 640163205 in words is "six hundred forty million, one hundred sixty-three thousand, two hundred five".