6340640891 has 16 divisors (see below), whose sum is σ = 6983553024. Its totient is φ = 5720250144.

The previous prime is 6340640869. The next prime is 6340640921. The reversal of 6340640891 is 1980460436.

It is a cyclic number.

It is not a de Polignac number, because 6340640891 - 2¹⁸ = 6340378747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6340640821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 446990 + ... + 460956.

It is an arithmetic number, because the mean of its divisors is an integer number (436472064).

Almost surely, 2^6340640891 is an apocalyptic number.

6340640891 is a deficient number, since it is larger than the sum of its proper divisors (642912133).

6340640891 is a wasteful number, since it uses less digits than its factorization.

6340640891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14770.

The product of its (nonzero) digits is 124416, while the sum is 41.

The square root of 6340640891 is about 79628.1413257901. The cubic root of 6340640891 is about 1850.8776834674.

The spelling of 6340640891 in words is "six billion, three hundred forty million, six hundred forty thousand, eight hundred ninety-one".