640134561 has 16 divisors (see below), whose sum is σ = 933285888. Its totient is φ = 387051600.

The previous prime is 640134559. The next prime is 640134563. The reversal of 640134561 is 165431046.

640134561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640134559) and next prime (640134563).

It is not a de Polignac number, because 640134561 - 2¹ = 640134559 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640134563) 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, 8281 + ... + 36726.

It is an arithmetic number, because the mean of its divisors is an integer number (58330368).

Almost surely, 2^640134561 is an apocalyptic number.

It is an amenable number.

640134561 is a deficient number, since it is larger than the sum of its proper divisors (293151327).

640134561 is a wasteful number, since it uses less digits than its factorization.

640134561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45452.

The product of its (nonzero) digits is 8640, while the sum is 30.

The square root of 640134561 is about 25300.8806368474. The cubic root of 640134561 is about 861.8342682151.

The spelling of 640134561 in words is "six hundred forty million, one hundred thirty-four thousand, five hundred sixty-one".