6640305165 has 48 divisors (see below), whose sum is σ = 12416000688. Its totient is φ = 3263597568.

The previous prime is 6640305163. The next prime is 6640305173. The reversal of 6640305165 is 5615030466.

6640305165 is a `hidden beast` number, since 6 + 640 + 3 + 0 + 5 + 1 + 6 + 5 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 722695689 + 5917609476 = 26883^2 + 76926^2 .

It is not a de Polignac number, because 6640305165 - 2¹ = 6640305163 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640305163) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 351747 + ... + 370143.

It is an arithmetic number, because the mean of its divisors is an integer number (258666681).

Almost surely, 2^6640305165 is an apocalyptic number.

6640305165 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

6640305165 is a deficient number, since it is larger than the sum of its proper divisors (5775695523).

6640305165 is a wasteful number, since it uses less digits than its factorization.

6640305165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19038 (or 19035 counting only the distinct ones).

The product of its (nonzero) digits is 64800, while the sum is 36.

The square root of 6640305165 is about 81488.0676234257. The cubic root of 6640305165 is about 1879.5880685106.

The spelling of 6640305165 in words is "six billion, six hundred forty million, three hundred five thousand, one hundred sixty-five".