640341561 has 12 divisors (see below), whose sum is σ = 863521712. Its totient is φ = 422082144.

The previous prime is 640341539. The next prime is 640341577. The reversal of 640341561 is 165143046.

640341561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 640341561 - 2⁵ = 640341529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640342561) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10290 + ... + 37236.

Almost surely, 2^640341561 is an apocalyptic number.

It is an amenable number.

640341561 is a deficient number, since it is larger than the sum of its proper divisors (223180151).

640341561 is an equidigital number, since it uses as much as digits as its factorization.

640341561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27128 (or 27039 counting only the distinct ones).

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

The square root of 640341561 is about 25304.9710728940. The cubic root of 640341561 is about 861.9271551788.

The spelling of 640341561 in words is "six hundred forty million, three hundred forty-one thousand, five hundred sixty-one".